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PLOS One logoLink to PLOS One
. 2026 Mar 25;21(3):e0320276. doi: 10.1371/journal.pone.0320276

The prevalence, prevention, and treatment of cardiovascular diseases in Twelve African Countries (2014–2019): An analysis of the World Health Organisation STEPwise approach to chronic disease risk factor surveillance

Wingston Felix Ng’ambi 1,*, Janne Estill 1, Fatma Aziza Merzouki 1, Cosamas Zyambo 2, Jonathan Chiwanda Banda 3, David Beran 4, Olivia Keiser 1
Editor: Muhammad Farooq Umer5
PMCID: PMC13016339  PMID: 41880473

Abstract

Introduction

Cardiovascular diseases (CVDs) are responsible for nearly a third of deaths globally. We conducted this study to understand the prevalence of history of CVDs, their prevention and treatment in twelve African countries using the World Health Organization STEPwise Approach to Surveillance (WHO STEPS) data.

Methods

We used secondary STEPS data extracted from 12 African countries between 2014 and 2019. CVD was defined as a self-reported history of heart attack, angina, or stroke. Weighted percentages, counts, weighted odds ratios (OR), and the corresponding 95% confidence intervals (95%CI) were computed using the R software. We fitted logistic regression models to select the predictor variables from a regression model for CVD prevalence, CVD prevention and CVD treatment binary endpoints.

Results

Amongst 60,294 individuals, the prevalence of CVD was 5%. The CVD prevalence was higher in older individuals, females, individuals with hypertension, smokers, people with high salt intake, and in certain countries. Eleven percent of the 23,630 individuals at high risk of CVD (≥40 years) but without a history of the disease received CVD prevention treatment. Amongst the 2,895 persons with CVDs, 22% received treatment and counselling for CVD: 34% (n = 215) receiving aspirin, 32% (n = 202) counselling for CVD risk factors, 11% (n = 66) statins, and 24% (n = 148) both statins and aspirin. The uptake of CVD treatment varied by hypertension status, sex, age and country.

Conclusion

The prevalence of CVD was relatively low and CVD treatment uptake was sub-optimal. Concerted efforts must be made to accelerate the diagnosis and expand treatment for CVDs in Africa if to curtail untimely deaths attributable to CVDs.

Introduction

Despite the relatively low prevalence of cardiovascular diseases (CVDs) in Africa compared to developed countries, there is evidence of a steady increase, which poses a significant public health concern. One of the aims of the United Nations Sustainable Development Goals is to reduce premature mortality from non-communicable diseases (NCDs) by a third by the year 2030 [1]. The CVDs, like coronary heart disease and stroke, are the most common NCDs globally responsible for an estimated 9.6 million male deaths and 8.9 million female deaths worldwide in 2019, of which 6.1 million of were among people aged 30–70 years [2]. Of these deaths related to CVDs, more than 75% occurred in low- and middle-income countries [3]. Heart attacks and strokes accounted for 85% of these fatalities [4]. Globally between 1990 and 2020 the age standardized DALYs for CVDs equal those of the communicable, maternal, neonatal and nutritional (CMNN) diseases combined.

While infectious diseases have historically been the primary focus of public health efforts in the region, CVDs are becoming a significant and increasing problem [5]. The prevalence of CVDs in Africa has been steadily increasing over the past few decades [5]. Despite the growing prevalence of CVDs in Africa, there is a lack of multi-country analyses assessing the full care continuum; from diagnosis to treatment; in this region. According to the Global Burden of Disease (GBD) project, prevalence of CVDs and mortality differ substantially between high-income and low-income regions. Particularly, Africa is seeing rising rates of diabetes, obesity, and hypertension; all of which are significant causes of CVD; but these patterns are not well-represented in international research initiatives. The region is understudied in comparison to more resourced locations because of issues with infrastructure, data availability, and healthcare systems [6]. Furthermore, while global trends in prevalence of CVDs and their associated risk factors have been extensively studied; Africa remains relatively understudied despite the rising burden of CVDs [6]. A dearth of comprehensive and localised studies that are suited to the region’s particular socioeconomic and healthcare contexts is further highlighted by recent reports from GBD collaborations that emphasise the need to shed light on the CVD epidemiology in Africa. Through region-specific analysis, these initiatives are starting to address modifiable risk factors; nevertheless, there are still gaps in assessing the effectiveness and implementation of interventions [7]. Efforts to address this growing health concern, like improved healthcare access, awareness campaigns, and research to develop region-specific prevention and treatment strategies, are critical [8,9]. For example, the World Health Organization developed the package of essential noncommunicable disease interventions (PEN) and related strategies (PEN-PLUS) for resource limited settings covering also the care of severe NCDs in these settings [2,10].

The prevalence of CVDs in Africa is influenced by a complex interplay of various determinants such as hypertension, diet, physical activity, tobacco use, alcohol consumption, age, gender, genetic factors, socio-economic deprivation (including poverty and limited access to healthcare), environmental factors (pollution and limited access to clean and safe water, and exposure to toxins), lack of awareness about CVD risk factors and prevention, and limited availability and quality of healthcare services and facilities in the region. These factors can significantly influence the diagnosis, treatment, and prevention of CVD [11,12]. In addition, the prevalence of CVDs in Africa is influenced by multiple determinants that vary across the regions, making it important to consider both spatial and temporal aspects when addressing the burden of CVDs in the region. The study acknowledges the complex interplay of determinants influencing the prevalence of CVDs in Africa, including socio-economic, environmental, and health system factors. This approach highlights the importance of considering regional variability, which is often overlooked in global analyses. By concentrating on Africa, the study fills a crucial gap in the literature, particularly in the context of limited healthcare resources and overlapping burdens of infectious diseases like HIV/AIDS and tuberculosis. Understanding the CVD determinants in Africa is crucial for developing effective strategies to reduce the prevalence of CVDs in Africa. For example, cessation of tobacco use, reduction of salt in the diet, eating more fruit and vegetables, regular physical activity, and avoiding harmful use of alcohol have been shown to be protective of CVD [13]. Furthermore, identifying the persons at highest risk of CVDs and ensuring they receive appropriate treatment can prevent premature deaths [14]. While the WHO STEPwise approach has provided a framework for monitoring NCDs, its data remain underutilized, especially in Africa [15]. This study addresses a critical gap in global CVD research by providing the first multi-country analysis of CVD prevalence, prevention, and treatment in Africa using WHO STEPS data. Its findings are not only relevant for Africa but also provide a template for utilizing similar data in other regions, thus contributing to the global effort to reduce NCD-related premature mortality.

Methods

Study design and setting

This is a secondary analysis of WHO STEPS data from countries with CVD data collected between 2014 and 2019 in Africa (see Box 1). This analysis includes data from 12 countries in Africa: Algeria, Benin, Botswana, Eswatini, Ethiopia, Kenya, Malawi, Morocco, São Tomé and Príncipe, Sudan, Uganda, and Zambia. The WHO STEPS assess risk factors for chronic non-communicable diseases and uses a multi-stage cluster sampling of households. One individual within the age range of the survey (18–69 years) was selected per household [16]. For example, Malawi’s STEPS survey in 2017 and Zambia’s STEPS survey in 2017 followed this methodology to capture critical health data for analysis [17,18]. The WHO STEPS use simple, standardized methods for collecting, analysing and disseminating data on key NCD risk factors in the countries. The survey covers key behavioural risk factors: tobacco use, alcohol use, physical inactivity, and unhealthy diet; as well as key biological risk factors: overweight and obesity, raised blood pressure, raised blood glucose, and abnormal blood lipids [16]. The survey is conducted using a stepwise procedure that begins with a questionnaire to collect data on risk factors (STEPS 1), progresses to basic physical examinations (STEPS 2), and concludes with the more intricate collection of blood samples for biochemical analysis (STEPS 3) [16]. The 2014–2019 period was selected because data on CVD were unavailable before this timeframe.

Box 1. WHO STEPWise Surveys (STEPS 1, 2 & 3) with cardiovascular disease data in African countries: 2014–2019.

Inline graphic

WHO package of essential noncommunicable intervention implementation

Across Africa, countries exhibit considerable heterogeneity in the timing and extent of adopting national NCD strategies and implementing the WHO Package of Essential Noncommunicable (PEN) disease interventions. The WHO PEN approach was first introduced globally in 2010 and WHO/AFRO has supported member states in PEN roll-out since at least 2008 [19]. In North Africa, Algeria formalized its national NCD strategic planning most recently (with an updated UNSDCF including NCDs from 2023) and Morocco has integrated PEN elements into its primary care cancer prevention efforts, with routine risk factor surveillance reported since 2018. In West Africa, Benin’s earlier NCD strategic plan (2014–2018) provides the backbone for current pilot PEN activities, and Sao Tome and Principe incorporated PEN into its NCD action planning upon joining WHO/AFRO’s regional frameworks in 2023. In East Africa, Ethiopia’s NCD strategic planning dates back to at least 2014–2016, followed by updated strategies into the early 2020s; PEN activities have been scaled in selected regions with quarterly monitoring. Kenya’s national NCD strategy (2015–2020) underpins systematic PEN roll-out across counties, and Uganda’s policy (published 2020) supports PEN training for frontline staff. Southern African countries show similar evolutionary progress: Botswana reports PEN guideline integration into primary care with service improvements; Eswatini’s strategic NCD plan dates from the 2012–2020 era; and Zambia has embedded PEN within its NCD framework, recently launching a PEN-Plus National Operational Plan in 2025 to expand care and training beyond primary care. Sudan adopted an NCD strategy as early as 2010–2015, though political instability has constrained consistent PEN implementation. In Malawi, PEN integration into the National Health Strategic Plan has guided initial district hospital training since the early 2020s, with ongoing expansion to peripheral centres.

Variables and data management

The most recent WHO STEPS data on CVD risk factors were extracted from each country. The data were managed in R (see 1_Create_dataset_for_analysis.R; Functions_rmph.R).

Outcome variables.

The primary outcome variable was whether an individual responded “yes” or “no” to the question “Have you ever had a heart attack, angina (chest discomfort caused by heart disease), or stroke (cerebrovascular accident or incident)?”, which we considered as a proxy for having CVD. We excluded 141,833 patients with missing CVD information. Prevention of CVD or uptake of treatment for CVD was assessed with the questions “Are you currently taking aspirin regularly to prevent or treat heart disease?” (yes/no), “Are you currently taking statins (Lovostatin/Simvastatin/Atorvastatin or any other statin) regularly to prevent or treat heart disease?” (yes/no) or “During the past three years, has a doctor or other health worker advised you to do any of the following: quit using tobacco or not start, reduce alcohol consumption or not start, reduce salt in your diet, reduce refined sugar in your diet, or eat at least five servings of fruits and/or vegetables each day?” (yes/no).

Predictor variables.

The predictor variables comprised the following known dichotomous risk and protective factors defined as follows: harmful alcohol use (defined as daily drinking and having at least 4 (for males) or 3 (for females) drinking occasions in the last 30 days) derived using the Alcohol Use Disorder Identification Test-C (AUDIT-C) [20]; low consumption of vegetables (i.e., “In a typical week, on how many days do you eat vegetables?” with less than five times a week being categorized as low consumption of vegetables); low consumption of fruits (i.e., “In a typical week, on how many days do you eat fruit?” with less than five times a week being categorized to have low fruit consumption); physical inactivity (less than 150 minutes of moderate-intensity physical activity per week) [21]; high salt intake (i.e., “How often do you add salt or a salty sauce such as soy sauce to your food right before you eat it or as you are eating it?” with those adding salt to food regularly or often eating processed food with high salt quantities are considered to have high salt intake); history of raised blood pressure (systolic blood pressure ≥160 and/or diastolic blood pressure ≥ 100 mmHg or currently on medication); and history of raised blood glucose (capillary whole blood value at least 6.1 mmol/L) [22]. We also included smoking history (currently smoking, previously smoking and never smoked); body mass index (<18.5, 18.5–24.0, 25.0–29.0, 30.0 + kg/m2; excluding pregnant women), sex of the respondent (male, female), age (15–29, 30–39, 40–49, 50–59, 60 + ; in completed calendar years), highest education level (none, primary, secondary, tertiary), occupation (government employee, non-government employee, self-employed, retired, or not working (including, e.g., students, unemployed)), type of residence (rural, urban), country, and marital status (never married, married, previously married).

The distribution of missingness in the analysed data is shown in Box 2. Overall, 26% of the individuals had missing data. The variable with the greatest missing data was diabetes with 8% missing data. Imputation was performed to handle the missing data because it allows for the inclusion of all available data in the analysis, ensuring more accurate and representative results. Different probability distributions were specified depending on the type of variable. For binary variables, such as presence or absence of a condition, we used a binomial distribution, which models the probability of a “success” or “failure” outcome. For categorical variables with more than two groups, such as education level or occupation, we applied a multinomial distribution that accounts for multiple outcome categories and ensures that the probabilities across categories sum to one. For continuous variables, including age, body mass index, and blood pressure, a Gaussian distribution was used to generate values based on the mean and variance of the observed data. These simulation models were implemented using random assignment based on the observed distribution of each variable, ensuring that imputed values reflected the empirical patterns in the data. This strategy allowed us to approximate the underlying data-generating mechanism more realistically, reduce bias from listwise deletion, and retain the full analytic sample.

Box 2. Proportion of missing data across variables used to assess cardiovascular disease prevalence in twelve African countries, 2014–2019.

Inline graphic

We opted for simulation-based imputation instead of standard MICE approaches for several reasons. First, the data exhibited complex patterns across multiple countries, including high inter-variable correlations and heterogeneity in variable distributions, which led to convergence issues and unstable chains when using MICE. Second, some variables had non-standard distributions or rare categories that are not easily handled by default MICE models. Third, simulation-based imputation allows direct specification of the appropriate distribution for each variable type (binomial, multinomial, Gaussian), ensuring that imputed values reflect the empirical distribution of the observed data. Missing categorical data were imputed using the base R function sample(), drawing from the observed distribution of non-missing values, while continuous variables such as age were simulated using rnorm() based on the observed mean and standard deviation, with results rounded to the nearest integer. Replacement values were therefore drawn from overall empirical distributions, and we acknowledge that this approach does not capture country-specific heterogeneity in risk factor distributions. To support reproducibility and ensure plausibility, we set a random seed prior to simulation and compared the distribution of imputed values with complete-case data (see sample simulation code below or 2_who_steps_ncd_data_cleaning_code_2024.R).

Finally, this approach avoids the iterative dependency structure of MICE, which can amplify biases in the presence of autocorrelation, while preserving sample size and statistical power. Furthermore, imputation is a common practice in epidemiological research to maintain data integrity and reduce bias due to incomplete datasets [23]. In order to ascertain the uptake of CVD prevention treatment, all the individuals aged at least 40 years were considered to be at risk of CVD and this formed the denominator for this analysis [24,25,26,27,28]. Furthermore, the WHO STEPS data analysis guide also considers the CVD naïve individuals aged at least 40 years as being at CVD risk [29,30].

Data analysisa

We set up the survey design before fitting any models and used the same weight variable, wstep1, throughout the analysis (see 3_CVD_Analysis_SSA_2024_FINAL.Rmd). For the CVD prevalence and prevention datasets, we defined a full complex design using primary sampling unit (psu) as the cluster, stratum as the stratification variable, and wstep1 as the sampling weight, with nesting enabled. For the treatment dataset, only wstep1 was available, so we applied a simple one stage design. All quasibinomial models for CVD prevalence were run on these survey design objects, ensuring that the sampling structure was properly accounted for. We also adjusted for inter country variation by including country fixed effects, rather than treating countries as random clusters. This allowed us to capture differences across countries in a clear and consistent way.

Our analysis is structured around the CVD care pathway; spanning diagnosis, treatment initiation, and counselling/adherence support; which provides a systematic framework to identify gaps in care and is particularly relevant in the African context, where resource constraints and variations in health system capacity can lead to substantial drop-offs at each stage of the cascade (see Box 3). Weighted percentages, counts, weighted odds ratios (OR), and the corresponding 95% confidence intervals (95%CI) were computed using the R software (version 4.3.2). The weighting variable from WHO STEPS was based on demographic characteristics of the general population from which a sample was taken (wstep1) [31]. We conducted a set of three weighted univariable and multivariable logistic regression analyses, with quasibinomial distributions [32], of the effects of the predictor variables on: CVD prevalence in the whole dataset, CVD prevention amongst the persons at risk of CVD, and CVD treatment (and counselling) among those with CVD (see 3_CVD_Analysis_SSA_2024_FINAL.Rmd).

Box 3. The Cardiovascular disease (CVD) care pathway from WHO STEPWise Surveys conducted across African countries (2014–2019). CVD = cardiovascular diseases.

Inline graphic

The quasibinomial distribution, an extension of the standard binomial distribution, is particularly suitable for survey data with binary outcomes, as it accounts for overdispersion (see 3_CVD_Analysis_SSA_2024_FINAL.Rmd). For each survey-weighted multivariable quasibinomial logistic regression model, survey weights were incorporated directly into the model fitting to ensure that parameter estimates reflected the complex sampling design. Weighted standard errors were calculated to account for unequal selection probabilities, thereby producing valid confidence intervals and p-values. We first fitted a full model including all candidate predictors and then applied backward variable selection using the stepAIC function from the MASS R package, retaining predictors that optimized model fit while respecting the survey weights [33]. The stepAIC function was used for stepwise selection, optimizing model fit by retaining predictors that minimized the AIC. Notably, the clinically important variables; age, sex, and hypertension status; were naturally retained in the final model based on the AIC criterion, so no variables needed to be forced into the model. We calculated the P-values for the bivariate logistic regression by comparing the model with the variable of interest and the empty model. Weighted quasibinomial logistic regression models with country fixed effects were used to account for country-level heterogeneity, as mixed-effects models were not preferred due to heterogeneity in survey design and instability with weighted data. Similarly, we calculated the P-values from adjusted models by comparing the final model with the model without the variable of interest. Wherever applicable the level of statistical significance was set at P < 0.05.

Sensitivity analyses (see 3_4_CVD sensitivity analysis 2025.R) were conducted to assess the robustness of the imputation assumptions by comparing results from the simulation-based imputation to a complete case analysis as shown in Box 4. This approach evaluated whether the main findings were influenced by the distributional assumptions used for imputing missing values. Based on the results there was perfect agreement of the coefficients from the imputed and complete case analyses coefficients (see Box 4).

Box 4. Sensitivity analysis of determinant coefficients for cardiovascular disease prevalence, comparing imputation and complete case analysis in twelve African countries, 2014–2019.

Inline graphic

Ethical consideration

Individual written consent was obtained from all participants before data collection the during the original WHO STEPS surveys. We requested access for secondary use of the data from the World Health Organization, the funder of the WHO STEPS surveys. The WHO STEPS survey datasets were downloaded from https://extranet.who.int/ncdsmicrodata/index.php/catalog/629 [22]. This dataset is anonymized with no identifiable information on survey respondents.

Results

Individuals included and excluded from the study

The distribution of individuals included in the study is shown in Fig 1. Of the 202,127 individuals included in the database, 60,294 (29.8%) were interviewed from 2014 onwards and included information on CVD.

Fig 1. Flow diagram of individuals included and excluded in the analysis: 2014–2019.

Fig 1

Characteristics of the study population

The characteristics of individuals included in this study are shown in Table 1. Of the 60,294 individuals, 44% were aged 15–29 years while 6% were aged 60 years or above. The proportions of males and females were similar. More individuals were from rural areas (60%) than urban areas (40%). About a third of the individuals had no education and almost half of the individuals were self-employed (see Table 1). The majority of individuals were currently married. The countries with highest numbers of respondents were Ethiopia (23%), Algeria (21%), and Sudan (16%).

Table 1. Characteristics of the study population, the CVD cases, and treatment uptake in twelve African countries between 2014 and 2019. The percentages for the study population are column percentages; for CVD cases and patients who received CVD treatment, the percentages are row percentages with the denominator being the whole study population within the respective category for CVD cases, and CVD cases within the respective category for patients who received CVD treatment.

Characteristics Study populationa CVD casesb Received CVD treatmentc
n % n % n %
Total 60294 100.0 2895 4.6 630 18.5
Age group
15-29 19351 44.1 748 3.6 71 9.2
30-39 15853 23.0 687 4.6 81 7.9
40-49 11563 16.6 553 5.1 109 19.4
50-59 7929 10.3 484 6.2 173 36.5
60+ 5598 6.0 423 8.4 196 45.4
Sex
Female 37010 48.8 1961 5.6 430 18.2
Male 23284 51.2 934 3.7 200 19.0
Area of residence
Rural 33718 59.7 1590 4.3 258 13.1
Urban 26576 40.3 1305 5.1 372 25.2
Highest level of education
None 20174 29.0 947 4.4 229 20.3
Primary 19647 35.0 1057 5.5 220 17.1
Secondary 14915 25.7 655 4.0 116 16.7
Tertiary 5558 10.2 236 3.8 65 24.4
Occupation
Government employee 4413 7.8 203 3.9 59 23.3
Non-Govt employee 4622 8.7 210 3.7 45 21.6
Non-paid/Retired 25400 36.2 1180 5.2 289 20.6
Self-employed 25859 47.3 1302 4.5 237 15.5
Marital status
Currently married 39949 68.5 2060 4.9 474 19.9
Formerly married 4019 5.4 243 6.8 49 12.8
Never married 16326 26.1 592 3.4 107 15.6
Having diabetes
No 58800 97.4 2814 4.6 608 18.4
Yes 1494 2.6 81 4.1 22 23.6
Having high cholesterol level
Yes 5926 6.2 279 5.0 79 18.6
No 54368 93.8 2616 4.6 551 18.5
Having hypertension
No 52772 91.5 2100 3.9 218 9.1
Yes 7522 8.5 795 11.8 412 52.6
High salt intake
No 40961 66.8 2005 4.7 467 21.0
Yes 19333 33.2 890 4.5 163 13.1
Low fruit uptake
No 14037 18.7 719 4.9 188 24.0
Yes 46257 81.3 2176 4.5 442 17.1
Low vegetable uptake
No 31130 46.3 1511 4.9 384 24.5
Yes 29164 53.7 1384 4.4 246 12.7
Physical activity level
Low Level 12325 16.4 562 4.6 199 34.5
Moderate level 12725 19.7 565 4.4 153 23.9
High level 35244 63.9 1768 4.7 278 12.9
Smoking history
Current 5047 10.2 258 5.2 45 16.4
Never 51899 83.2 2425 4.4 518 17.6
Previous 3348 6.7 212 5.8 67 29.6
Harmful alcohol use
No 58491 97.1 2775 4.6 615 18.7
Yes 1803 2.9 120 5.4 15 14.0
BMI
< 18.5 7899 15.5 331 3.5 50 12.9
18.5-24 29966 53.0 1426 4.7 199 10.8
25-29 12417 17.5 617 5.2 180 27.4
30+ 10012 14.0 521 4.9 201 38.8
Survey year
2014 10887 10.8 712 8.7 109 10.6
2015 18833 39.2 926 4.3 116 8.0
2016 14677 37.3 532 3.7 232 38.6
2017 13479 12.5 635 4.8 147 14.7
2019 2418 0.2 90 3.4 26 27.9

ais the denominator for b when calculating the prevalence of CVD cases

bis the denominator for c when calculating uptake of CVD treatment amongst the CVD cases

Of the 60,294 individuals, 9% had hypertension, 6% had high cholesterol and 3% had diabetes. Furthermore, 19,333 (33%) reported high salt uptake, 45,207 (81%) low fruit uptake, and 28,905 (54%) low vegetable uptake (Table 1). The prevalence of low level of physical activity was reported as 16% while the prevalence of reported high level of physical activity was 65%. A total of 1,803 (3%) of the 60,294 individuals reported using alcohol in a harmful way. Furthermore, 5,047 (10%) and 3348 (7%) of the 60,294 individuals reported being current and previous smokers, respectively. The prevalence of reported current smoking was 10% while 6% of the individuals had previously smoked or used tobacco. The prevalence of measured underweight was 10% and the prevalence of overweight (i.e., BMI of at least 30 kg/m2) was 14%. The highest number of individuals were interviewed in 2015 or 2016 and the least in 2019.

Care cascade for the cardiovascular disease

Across the 12 study countries, a substantial gap was observed along the CVD care cascade in Fig 2. While the total eligible population ranged widely, only a small proportion had a documented diagnosis of CVD, and an even smaller fraction received treatment. For example, in Algeria, out of 6,955 individuals, only 415 (6.0%) had a CVD diagnosis and 178 (2.6%) were on treatment. Similarly, in Malawi, 312 of 4,186 participants (7.5%) were diagnosed, but just 64 (1.5%) received treatment. Diagnosis rates were particularly low in Kenya (0.4%) and Eswatini (4.3%), while Morocco showed the highest diagnosis proportion (3.3%). Treatment coverage among those diagnosed also varied widely, with Algeria achieving 42.9%, Morocco 36.2%, and Zambia only 15.0%. Overall, the cascade illustrates that fewer than one in ten individuals are diagnosed, and less than half of those diagnosed receive treatment, underscoring major gaps in CVD detection and management across the region.

Fig 2. Cardiovascular disease care cascade in twelve African countries, 2014–2019.

Fig 2

Prevalence of CVD and factors associated with CVD in twelve countries of Africa

The prevalence of CVD was 5% (2895/60,294) and increased with age (Table 1). The prevalence of CVD was higher in females than males, in urban than rural areas, and in individuals with hypertension, using alcohol harmfully, or being obese or overweight. Uganda (9%), Malawi (7%), Botswana (6%), Algeria (6%) and Kenya (6%) had the highest, and Sudan (1%), Zambia (3%), and Morocco (3%) the lowest prevalence of CVD (Table 1).

Older age, male sex, certain countries of residence, having hypertension, high salt uptake, and current or previous smoking were significantly associated with higher risk of CVD. The adjusted estimates show that there was an increasing trend in CVD with age (Fig 3). After adjusting for sex, area of residence (urban vs rural), highest education level, marital status, country of residence, having hypertension, high salt intake, physical activity level, and smoking status, the individuals aged 50−59 or at least 60 years were more likely to have CVD (aOR: 1.39, 95%CI: 1.17–1.66 and aOR: 1.67, 95%CI: 1.36–2.07, respectively) than those aged 15−29 years. Males were less likely to have CVD than females (aOR: 0.65, 95%CI: 0.54–0.72, P < 0.001). Country-specific differences highlight the role of regional factors, with Sudan showing the lowest risk and Uganda the highest (Table 2). Individuals with hypertension were almost three times more likely to have CVD compared to those without hypertension (aOR: 2.68, 95%CI: 2.32–3.10, P < 0.001). Similarly, individuals with high salt uptake were 23% more likely to have CVD than those without high salt uptake (aOR: 1.23, 95%CI: 1.02–1.49, P = 0.03). Those who never smoked tobacco were less likely to have CVD compared to those currently smoking (aOR: 0.69, 95%CI: 0.55–0.86, P < 0.0001).

Fig 3. Determinants of cardiovascular disease prevalence in twelve African countries, 2014–2019.

Fig 3

Table 2. Characteristics of persons who were at risk of cardiovascular diseases, the uptake of prevention of CVD and the factors associated with the uptake of prevention services for CVD in Africa between 2014 and 2019.

Characteristics Total Received prevention
n % n %
Total 23630 100 2665 11.3
Age group
40-49 11010 51 711 5.8
50-59 7445 31.2 997 11.6
60+ 5175 17.8 957 16.6
Sex
Female 13763 46.6 1893 12.7
Male 9867 53.4 772 6.8
Area of residence
Rural 12560 55.9 878 5.1
Urban 11070 44.1 1787 15.2
Highest level of education
None 10123 36.5 996 6.8
Primary 7526 34.8 825 9.5
Secondary 4281 20.6 554 11.7
Tertiary 1700 8.1 290 16.7
Occupation
Government employee 1974 10.2 289 13
Non-Govt employee 1748 8.6 160 8.8
Non-paid/Retired 9905 36.3 1450 12.9
Self-employed 10003 44.9 766 6.2
Marital status
Currently married 18714 85.9 2032 9.6
Formerly married 2296 7.8 291 9.8
Never married 2620 6.3 342 8.9
Country
Algeria 3375 27.1 725 20.1
Benin 1894 1.7 66 3.8
Botswana 1408 0.5 336 21.7
Eswatini 1189 0.2 191 15.6
Ethiopia 3105 20.5 133 2.7
Kenya 1626 13 80 4.9
Malawi 1518 5.8 77 4.5
Morocco 2680 0 426 14.2
STP 897 0.2 115 13.8
Sudan 3219 16.6 415 11.8
Uganda 1184 8.9 41 2.9
Zambia 1535 5.5 60 4
Having diabetes
No 23012 97 2561 9.4
Yes 618 3 104 14.6
Having high cholesterol level
Yes 2899 8.7 433 11.7
No 20731 91.3 2232 9.3
Having hypertension
No 19015 84.3 618 3.4
Yes 4615 15.7 2047 42.6
High salt intake
No 16856 70.7 2000 11.4
Yes 6774 29.3 665 5
Low fruit uptake
No 5693 19.4 843 14.4
Yes 17937 80.6 1822 8.4
Low vegetable uptake
No 13099 50.9 1776 12.7
Yes 10531 49.1 889 6.3
Physical activity level
Low Level 5588 20.2 928 16.2
Moderate level 5013 20.3 732 13.3
High level 13029 59.5 1005 6
Smoking history
Current 2342 11.7 158 6.4
Never 19338 77.2 2252 9.6
Previous 1950 11.1 255 12.2
Harmful alcohol use
No 22800 96.2 2633 9.8
Yes 830 3.8 32 2.5
BMI
< 18.5 2990 14.9 195 5.7
18.5-24 10199 46.1 637 5.1
25-29 5612 21.4 808 13.9
30+ 4829 17.6 1025 19.2
Survey year
2014 3781 9.6 568 4.1
2015 6625 35.2 279 3.6
2016 6594 43.6 1140 16.9
2017 5733 11.4 563 4.3
2019 897 0.2 115 13.8

STP= Sao Tome and Principe; BMI= Body mass index

Uptake of CVD prevention amongst the individuals aged at least 40 years in twelve countries of Africa

The characteristics of the 23,630 individuals who were at risk of CVD and interviewed on the uptake of CVD prevention treatment and counselling are shown in Table 2. Of these 23,630 individuals, the majority (51%) were aged between 40 and 49 years, 53% were males, 56% were from rural areas, 37% had no education, 27% were from Algeria while less than 0.1% were from Morocco, 3% had diabetes, 9% had high cholesterol level, 16% had hypertension, 29% had high salt uptake, 81% had low fruit uptake, 49% had low vegetable uptake, 20% had low physical activity, 12% were current tobacco smokers, and 4% were harmful alcohol users.

Only 11% received any form of prevention or counselling, highlighting a major prevention gap. The distribution of the uptake of CVD prevention by the characteristics of the respondents is shown in Fig 4. People aged at least 60 years, those with BMI of at least 30, those who had previously smoked tobacco, those with low physical activity and those with tertiary education had the highest uptake of CVD prevention. Similarly, higher uptake of CVD prevention was observed amongst the females, urban residents, those with diabetes, those with hypertension, those with low salt uptake, and those who were not harmful alcohol users.

Fig 4. Factors linked to uptake of preventive cardiovascular disease treatment in twelve African countries, 2014–2019.

Fig 4

The factors associated with the uptake of CVD prevention are shown in Fig 4. Individuals who were aged at least 50 years were more likely to get CVD prevention compared to those who were aged between 40 and 49 years. Males were less likely to get CVD prevention compared to females (aOR: 0.73, 95%CI: 0.58–0.932, P < 0.0001). Urban residents are more likely to receive prevention (aOR: 1.65, 95%CI: 1.33–2.04, P < 0.0001) than their rural counterparts. Educational attainment influences uptake, with individuals having a tertiary education showing the highest uptake (Fig 4). Previous smokers had higher (aOR: 1.17, 95% CI: 0.83–1.64) and non-smokers lower uptake (aOR: 0.88, 95% CI: 0.64–1.20) compared with current smokers. Individuals with hypertension were 17 times more likely to get CVD prevention compared to those without hypertension (aOR: 16.65, 95%CI:13.93–19.91, P < 0.0001). There were also country variations in uptake of treatment for preventing CVDs (see Fig 4). These findings suggest that targeted interventions addressing these modifiable factors could improve CVD prevention uptake in Sub-Saharan Africa.

Uptake of treatment for CVDs in twelve countries of Africa

The treatment and counselling received by the respondents with CVD is shown in Fig 1. A total of 630 (22%) of the 2895 individuals with CVD received treatment and counselling. Of these 630 patients, 32% received counselling, 34% received aspirin (but no statins), 11% received statins (but no aspirin), and 24% received both statins and aspirin. The distribution of the uptake of treatment amongst the persons who had CVD is shown in Table 1. Individuals aged below 40 years had lower treatment uptake than individuals aged at least 50 years. The highest treatment uptake was observed amongst those with hypertension (53%), previous smoking history (30%), and obesity (27%) or overweight (40%). The CVD cases in Sudan showed the highest treatment uptake (42%) while the CVD cases in Kenya showed the lowest treatment uptake (5%).

The factors associated with CVD treatment uptake are shown in Fig 5. Age has a major impact on treatment uptake; those in the 50–59 and 60 + age groups were far more likely to get therapy than people in the 15–29 age range. For instance, the adjusted model showed a robust correlation between age increased treatment uptake, with an aOR of 2.31 (95%CI:1.39–3.84) for those aged 50–59 and 2.90 (95%CI: 1.75–4.82) for those aged 60 + compared to the 15–29-year-old. In the adjusted model, sex did not significantly affect treatment uptake; males had an OR of 1.36 (0.97–1.89) compared to females. However, urban dwellers were more likely than their rural counterparts to receive therapy (OR 1.36, 0.97–1.90). Individuals with hypertension were 7 times more likely to take treatment for CVD than those without hypertension (aOR: 7.19, 95%CI: 5.15–9.78, P < 0.001), and individuals with low vegetable uptake were less likely to take CVD treatment than those who had high uptake of vegetables (aOR: 0.58, 95%CI: 0.54–0.83, P = 0.003). Kenya, Malawi and Zambia had lower CVD therapy uptake compared to Algeria while Sudan had a similar CVD uptake compared to Algeria. With ORs of 1.37 (0.69–2.74), 0.74 (0.50–1.10) and 1.09 (0.70–1.72), respectively, diabetes, physical inactivity and current smoking demonstrated a weaker or non-significant correlation.

Fig 5. Factors linked to treatment uptake amongst those diagnosed with cardiovascular disease in twelve African countries, 2014–2019.

Fig 5

Discussion

This study examined the prevalence of CVD and the uptake of both preventive and treatment services across twelve African countries, drawing on nationally representative WHO STEPS data. The discussion is organized around three key themes: CVD prevalence, prevention, and treatment uptake. This is followed by an outline of the study’s strengths and limitations, and finally the conclusions and recommendations.

Discussion for CVD prevalence

The overall CVD prevalence of 5% in this study was consistent with findings from a meta-analysis that found the CVD prevalence to be 7% in SSA [34]. In contrast, other regions exhibit higher CVD prevalence, for example, Europe, South and Southeast Asia and Central Asia have some of the highest CVD mortality rates globally [35,36]. Similarly, North America has a high prevalence of CVD, with projections indicating that 61% of U.S. adults will have some form of cardiovascular disease by 2050 [36]. The low rates of CVDs in Africa may be attributed to limited diagnostic capabilities for confirmation [5]. In addition, the age distribution of the sample, including the exclusion of adults over 69 years, may have contributed to lower estimates, as CVD risk increases with age. Both factors should be considered when interpreting these findings relative to regional prevalence estimates. As people get older, their heart and blood vessels naturally work less efficiently, which greatly increases the risk of heart disease and stroke [37] and this trend was also observed in this study. The implication is to provide the screening services to persons aged 40 years and above, as these are documented to have a high risk of CVD [3,38,39].

Our study is also consistent with what has been reported in other settings that more females had CVD than males [40]. Therefore, CVD prevention may be significantly increased by offering sex-specific risk factor monitoring and intervention strategies [3,40]. High blood pressure is one of the risk factors for CVD that has a high prevalence and is linked to strong evidence of causation [41]. Meta-analyses have shown that lowering blood pressure can effectively prevent CVDs [40,42,43]. Further evidence suggests that smoking is a key factor responsible for more than 30% of the CVD mortality [44,45] [47, pp. 2011–2018]. Therefore, implementing interventions aimed at smoking cessation or preventing exposure to passive smoking has the potential to further reduce the risk of CVD.

Our study found that the prevalence of CVD varies geographically throughout Africa, which emphasises how crucial it is to take regional variances into account when creating focused healthcare interventions. In addition, contextual elements such as the varying stages of national NCD program implementation, differences in the rollout of WHO PEN interventions, and diverse cultural and socioeconomic environments likely contribute to the observed patterns [46]. Incorporating these broader contextual influences aligns with evidence from other regions, including Europe, where cultural practices, socioeconomic structures, and policy environments shape both CVD prevalence and management. Including these considerations provides a more comprehensive explanation for cross-country variation in our findings. For example, dietary practices, public health policies, and healthcare infrastructure have all been linked to differences in the burden of CVD between Western and Southern European countries [47]. These results highlight the necessity of investigating and addressing the fundamental causes of regional variations in CVD prevalence in order to create efficient, situation-specific management and prevention plans in Africa.

The increased prevalence of CVDs in Africa is largely caused by high salt intake, especially because it is linked to hypertension, a key risk factor for heart disease and stroke. According to a meta-analysis, the World Health Organization’s recommended daily limit of 2 grammes of salt is frequently exceeded in Africa, raising the risk of hypertension and cardiovascular diseases [48]. Regions such as Europe, North America, and Australia have successfully reduced salt consumption through public health measures [49]. For example, in order to prevent hypertension, the American Heart Association recommends avoiding meals high in sodium and focusing on controlling blood pressure through a heart-healthy diet. In Africa, implementing food-based dietary guidelines (FBDGs) has been successful in reducing risk factors for CVD, including high blood pressure and cholesterol. According to studies, choosing a diet that complies with current dietary guidelines decreases blood pressure and cholesterol, which should reduce the risk of CVD by one-third in middle-aged and older people in good health [50]. It has been demonstrated that the Dietary Approaches to Stop Hypertension (DASH) diet, which places an emphasis on consuming less salt, lowers blood pressure, cholesterol, and saturated fats, all of which are risk factors for CVD [51]. In order to prevent premature mortality, lower the increasing burden of non-communicable diseases in Africa, and limit CVD risk factors like hypertension and hypercholesterolemia, it is imperative that high salt intake be addressed through multi-sectoral policies and customised FBDGs.

The CVD were shown to be three times more common among people with hypertension in Africa than in those with normal blood pressure. This pattern is similar to findings from other locations, but the risk varies. Due in large part to improved blood pressure control and easy access to antihypertensive medication, the relative risk of CVD among hypertensive people in Asia, Latin America, North America and Europe is two to three times higher compared with those without hypertension [52,53,54,55]. This emphasises the critical need for better blood pressure screening, reasonably priced antihypertensive drugs, and strong primary healthcare interventions because hypertension is a major modifiable risk factor for CVD. Ignoring this problem will increase the already increasing burden of CVD, worsen health disparities, and put further strain on the region’s already vulnerable healthcare infrastructure. Effectively managing hypertension could lower the risk of CVD considerably and help achieve international goals such as the Sustainable Development Goal of lowering premature mortality from non-communicable diseases by 2030.

Discussion for CVD prevention

Comparing Africa to other regions, the region’s 11% adoption rate of CVD preventative therapy is far lower. Due to strong healthcare systems, easily accessible drugs, and effective follow-up procedures, the uptake of preventative medicines like aspirin, statins, and antihypertensives approaches 50%–60% in high-income nations like Europe, North America, and Australia [56,57]. Although acceptance rates in Asia vary, they are typically also high, ranging from 20% to 40%, especially in cities with more advanced healthcare facilities [54,58]. Similar to Africa, Latin America shows also uptake rates of between 30% and 40%, however rural areas encounter similar difficulties [59]. Higher CVD morbidity and mortality, higher healthcare costs as a result of acute care needs, and growing disparities in healthcare access are only a few of the serious ramifications of the poor uptake in Africa [60]. In order to improve CVD preventive care and lower the rising burden of CVD in the region, this finding emphasises the urgent need for targeted interventions like bolstering primary healthcare systems, guaranteeing affordable access to necessary medications, delegating tasks to community health workers, and implementing international initiatives like the WHO’s HEARTS program.

According to our study, men were much less likely than women to obtain CVD prevention. This pattern is in accordance with research from other areas, such as Europe and Asia, where women are more likely to follow preventative care recommendations and have higher rates of healthcare utilisation [61]. Because of maternity and reproductive health services, women engage with healthcare systems more frequently, which opens up potential for early CVD risk assessment and intervention. Furthermore, because of cultural norms, a perceived lack of sensitivity to chronic diseases, and poorer health-seeking behavior, men may be less involved in preventive healthcare [62]. This gender gap is made worse in Africa by structural issues including inadequate health care. Systemic issues including low health literacy and resource shortages, especially in rural regions where men predominate, worsen the gender gap in Africa. Public health is significantly impacted by men’s lower adoption of CVD prevention. Addressing these inequities is crucial because men in Africa are more likely to suffer from risk factors such smoking, excessive alcohol use, and hypertension [63]. This disparity might be closed and the burden of CVD considerably decreased with gender-specific programs that focus on male health behaviour, raise knowledge, and enhance access to CVD preventive treatment.

Compared to their rural counterparts, urban dwellers had almost double the likelihood of receiving CVD prevention. This gap between urban and rural areas is consistent with international findings showing that urban areas have better access to, infrastructure for, and awareness of, healthcare [64]. Preventive programs that encourage CVD screening and early intervention are more prevalent in urban locations, as are healthcare facilities and specialised physicians. On the other hand, access to preventative treatment is frequently restricted in rural Africa due to factors like lower socioeconomic status, understaffed healthcare facilities, and geographic inaccessibility [65]. Given that the majority of people in Africa live in rural areas, the effects of this urban-rural divide are crucial. Rural dwellers will continue to be disproportionately susceptible to untreated cardiovascular disease risk factors in the absence of focused efforts, which will increase morbidity and mortality. Increasing access to CVD prevention treatment in rural areas through community-based initiatives, mobile health interventions, and decentralised healthcare services must be a top priority for policymakers. For equal progress towards reaching the Sustainable Development Goal of lowering premature mortality from non-communicable diseases by 2030, this gap must be closed.

Discussion for CVD treatment uptake

There is not much evidence on the uptake of treatment for CVD in Africa. Just 22% of people with CVD in Africa received treatment, indicating a significant gap in the provision of necessary care for those impacted. This number is significantly lower than in other continents like North America and Europe, where more than 70% of people with CVD receive treatment because of their well-established healthcare systems, easy access to drugs, and successful preventative initiatives [66]. Treatment rates range from 40% to 60% across Asia and Latin America, which reflects attempts to scale up the management of chronic diseases and improve healthcare accessibility [67]. The glaring disparity in treatment uptake highlights the persistent issues in Africa, such as the lack of adequate healthcare infrastructure, the high cost of necessary pharmaceuticals, low knowledge, and a paucity of qualified medical personnel, especially in underserved and rural areas [58]. This low treatment rate has serious ramifications because untreated CVDs greatly raises the risk of negative outcomes like heart attack, stroke, and early death. Given the continued challenges with communicable diseases and the increasing burden of CVDs in Africa, region-specific therapies are desperately needed. To close this gap, it is crucial to address socioeconomic barriers, integrate CVD care into basic healthcare, and provide access to cheap treatment.

In Africa, those with hypertension were seven times more likely than those without to receive treatment for CVD, highlighting that hypertension not only serves as a crucial starting point for CVD care but also aids in its diagnosis, given its well-established role as a major risk factor. This pattern is consistent with findings from North America and Europe, where clinical guidelines prioritise screening and treatment for hypertensive people [68,52]. However, missed chances for early detection and management of CVD among other high-risk populations, such as those with diabetes, obesity, or tobacco use, are reflected in the poorer treatment uptake among non-hypertensive adults in Africa [67]. To close this gap and guarantee fair treatment access for all at-risk persons, thorough risk assessment instruments and integrated care pathways must be expanded. In order to meet global goals like the WHO’s “25 by 25” program to reduce early deaths from non-communicable illnesses and lessen the rising burden of CVD in Africa, these measures must be scaled up.

CVD care cascade

A full understanding of CVD care requires looking at the entire cascade, from screening and diagnosis through to treatment initiation and long-term adherence. The current WHO STEPS dataset does not include information on CVD screening, which limits the ability to assess the full pathway of care. Even so, our analysis shows major gaps: only 11% of participants reported receiving any form of CVD preventive therapy, and just 22% of those with CVD were on treatment. These figures point to large losses at multiple points in the continuum. The gaps are especially evident among rural populations and men, who were less likely to be receiving care [5]. To strengthen future analyses, WHO STEPS surveys should collect data not only on diagnosis and treatment but also on screening and adherence [5]. Alongside this, complementary qualitative work or topic modelling could help explain country-specific barriers, giving clearer insight into how to improve both equity and coverage in CVD care.

To address these gaps, targeted interventions should be prioritized, including integrating CVD care into primary healthcare systems, task-shifting responsibilities to community health workers, and ensuring the availability of low-cost essential medications. When compared to other LMICs, such as countries in Asia and Latin America, Africa’s CVD preventive and treatment uptake remains substantially lower, underscoring persistent structural and socioeconomic barriers [5]. Future WHO STEPS iterations could further enhance policy relevance by including detailed care cascade indicators and socioeconomic measures, enabling researchers and policymakers to identify critical points for intervention and design context-specific strategies to improve CVD outcomes.

All stages of the CVD cascade (screening, diagnosis, treatment, etc.) depend on people’s recall of prior care and on each prior step being completed, so country differences often reflect how many people ever got checked rather than just true disease rates [69]. For example, in Morocco’s 2017 survey many older adults may have had routine blood‐pressure or cholesterol tests in strong primary care settings and thus report knowing their diagnosis, whereas in Ethiopia’s 2015 survey a similar person in a rural area may never have been screened at all. That means Morocco can show a higher percentage “diagnosed” or “treated” simply because more cases were detected, while underdiagnosis in low‐resource settings like Malawi or Benin shrinks all subsequent steps. Using self‐reported pathways also invites recall and selection biases – for instance, educated or urban patients who seek care are more likely to remain in the cascade – as experts have warned of “recall bias in self-reported information” and poor comparability across surveys [70]. In practice, therefore, differences in cascade figures between countries (e.g., Algeria vs Sudan or Kenya vs Uganda) should be seen as reflecting both epidemiological variation and health-system capacity (screening reach, diagnostic availability), not as direct measures of one country “performing” better than another.

Strengths and limitations

This is to our knowledge the first multi-country study analyzing prevalence and uptake of CVD treatment in Africa using WHO STEPS. There are some analyses at country level using other sources, but such datasets, unlike WHO STEPS, are not usually nationally representative [5,34]. Therefore, the major strengths of this study were the large sample size and its representativeness, which potentially allows the analysis to improve operational practice and inform policy change. Another strength is that the study covered twelve countries and thus provides a good picture of CVD prevalence and treatment in Africa in general.

However, several limitations should be noted. First, the analysis did not incorporate country-level health system indicators, such as the availability of essential medicines (e.g., aspirin or statins) or the existence of national NCD strategies, which may partly explain inter-country differences. Second, the study relied on self-reported information regarding heart attacks, CVD treatment, and related risk and protective factors. This approach may introduce diagnostic and recall bias, particularly in settings with limited healthcare access, where individuals may be unaware of or unable to accurately report their condition or treatment history. These factors should be considered when interpreting the results and may provide avenues for future research. We were, however, unable to estimate the extent of underestimation or overestimation of the reported CVD-related risk and protective factors with heart attack and CVD treatment uptake. Although treatment-related analyses incorporated STEPS individual sampling weights, primary sampling units and strata could not be specified due to errors arising from the pooled, harmonized dataset, which may have led to underestimated standard errors and overly narrow confidence intervals, and no formal sensitivity analyses using alternative survey specifications were conducted. Furthermore, the data were available for only one survey round per country, limiting assessment of within-country temporal trends. Although survey years varied across countries, survey year was not significantly associated with CVD risk; however, residual temporal heterogeneity may still affect between-country comparisons.

The study only looked at the general CVD conditions and does not provide information on the type of CVD that the individuals had. Having such information could help to choose the most suitable risk reduction interventions. Another limitation is that the WHO STEPS does not capture information on screening for CVDs although such information would better help understand the care cascade from those eligible for screening to uptake of treatment. Besides, wealth quintile is not captured in most of the WHO STEPS surveys despite wealth index being paramount in determining equity and inequity of health outcomes. For example, there is evidence from multiple countries across the world that wealthier individuals had higher prevalence of CVD than poorer ones [71,72].

Although wealth quintile data were unavailable, urban/rural residence, gender, and education were used as proxies to explore socioeconomic gradients in CVD prevention and treatment uptake. Urban residents and women were more likely to receive care, reflecting disparities in healthcare access and health-seeking behavior. While country-specific differences (e.g., Uganda vs. Sudan) were observed, they were not fully contextualized. Future work could explore the underlying reasons such as healthcare access, survey methodology, or cultural factors using qualitative approaches or text-based analyses like topic modeling to better understand country-level patterns.

Conclusion

In conclusion; using a sizable and representative dataset from twelve countries, our work offers a crucial insight into the prevalence of CVDs and the uptake of its treatment in Africa. The African context highlights gaps in diagnosis and treatment for CVD compared to Europe, Asia, and North America. People with hypertension are seven times more likely to undergo treatment, making hypertension a crucial point of entry for CVD therapy. Important risk factors, such as smoking and excessive salt consumption, highlight the need for multi-sectoral treatments like smoking cessation programs and nutritional recommendations. Notwithstanding its advantages, such as its sizable sample size and representativeness, the study’s dependence on self-reported data and its absence of details on wealth indices and particular forms of CVDs point to areas that require more investigation. Achieving global health goals like the Sustainable Development Goals and lowering the rising burden of CVDs in Africa depend on closing these disparities and putting equitable, evidence-based interventions into place.

Supporting information

S1 File. 1_Create_dataset_for_analysis.

R R script used to generate the dataset for analysis.

(ZIP)

pone.0320276.s001.zip (38.7KB, zip)
S2 File. Sample simulation code.

(DOCX)

pone.0320276.s002.docx (15.4KB, docx)

Acknowledgments

The authors would like to thank the World Health Organisation for granting access to use the WHO STEPS data sets for Africa.

Data Availability

The data used in this study may be accessed at https://extranet.who.int/ncdsmicrodata/index.php/catalog/629.

Funding Statement

The author(s) received no specific funding for this work.

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Decision Letter 0

Muhammad Farooq Umer

12 Aug 2025

Dear Dr. Ng'ambi,

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Additional Editor Comments:

Based on the reviewers’ thorough evaluations, it is evident that the manuscript requires substantial revisions before it can be considered for further processing. The reviewers have identified significant concerns affecting multiple sections of the work. Specifically, the case definition lacks sufficient clarity and consistency, methodological details are insufficiently described, the interpretation of the findings requires alignment with the evidence presented. Furthermore, the overall writing expression requires improvement for clarity, conciseness, and academic rigor, including correction of grammatical inconsistencies and refinement of sentence structure. Only upon satisfactory resolution of these concerns can the manuscript be considered for re-review.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: I Don't Know

Reviewer #2: Yes

Reviewer #3: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #1: Introduction and discussion sections talk on SSA but this study does include data from Morroco and Algiers and therefore not sure whether one should talk on SSA. The study represents Africa.

Line 121 to 123; please correct the statement. Those that were excluded were the 141833 patients that did not have information on cvd. please correct.

Reviewer #2: 1. Clarity and Structure

The paper is dense in places. Consider improving the flow by: Splitting long paragraphs into digestible chunks. Adding section headers in the Results and Discussion for CVD prevalence, CVD prevention, and CVD treatment uptake to improve readability. Summarizing key stats in bulleted lists or tables where appropriate.

2. Introduction: Need for a Clearer Research Gap

While the introduction covers background well, it could more clearly state the specific gap this study addresses. Suggestion: “Despite the rising burden of CVDs in SSA, there is a lack of multi-country analyses assessing the full care continuum — from diagnosis to treatment — in this region.”

3. Methods: More Detail Needed

Imputation of Missing Data: More detail on the simulation approach used (binomial, multinomial, Gaussian) would help replicate or critique the methodology. Why was this approach chosen over multiple imputation or complete-case analysis? Definition of ‘At Risk’ Individuals: You define “at risk” as ≥40 years old. Justify this age cutoff more explicitly with references or explain why this was chosen over risk factor-based definitions.

4. Results: More Visuals Could Help. Consider including: A map showing prevalence of CVD by country. Bar plots or forest plots for adjusted odds ratios.

5. Discussion: Slight Redundancy. Some points in the discussion (e.g., treatment disparities by gender, hypertension as a CVD risk) are repeated across several paragraphs. Try to consolidate and avoid redundancy.

6. Limitations: A Few More Could Be Added. The study doesn't account for country-level health system indicators (e.g., availability of aspirin or statins, national NCD strategies), which could partly explain inter-country differences. There may be diagnostic bias due to self-reported CVD, especially in settings where people have less access to healthcare.

7. Technical and Stylistic Suggestions

- Language & Grammar:Replace awkward or redundant phrasing: "the CVD cases from Sudan had the highest..." ➜ "CVD cases in Sudan showed the highest treatment uptake..." “an individual with hypertension were” ➜ “individuals with hypertension were”

- Consistency:

Use either "sub-Saharan Africa (SSA)" or "SSA" consistently. Be consistent in using "CVD prevention" vs "CVD prophylaxis" — stick to one term.

- Data Reporting: Some statistics could be presented more concisely: Example: "Of the 23,630 persons at risk of CVD, 11% received prophylaxis or counselling." You could split this to say: “Only 11% received any form of prophylaxis or counselling, highlighting a major prevention gap.”

Reviewer #3: This manuscript addresses a critical public health issue—cardiovascular disease (CVD) prevalence, prevention, and treatment in sub-Saharan Africa—using WHO STEPS data. The multi-country scope and large sample size are notable strengths, and the topic aligns well with the journal’s readership. However, the manuscript would benefit from clearer methodological details, improved interpretation of findings, and refinement of the discussion to provide more actionable policy insights.

1.Clarity on Case Definitions

- The operational definition of “CVD” in this study is based on self-reported history of heart attack, angina, or stroke. This should be emphasized as a major limitation in the abstract and discussion. It may underestimate the true prevalence of CVD due to lack of diagnostic confirmation.

- Please clarify whether “angina” was assessed by standardized questions (e.g., Rose questionnaire) or a single self-report item.

2.Methodological Details

- The imputation strategy is briefly described (binomial, multinomial, Gaussian simulations). Please elaborate on:

The proportion of missing data for each variable.

Justification for using simulation instead of standard MICE approaches (beyond the “autocorrelation” statement).

Sensitivity analyses to assess robustness of imputation assumptions.

The use of weighted logistic regression is appropriate, but details of how survey weights were incorporated into multivariable models should be expanded.

3.Selection of Predictor Variables

- The stepwise selection via AIC is described, but a rationale for retaining or excluding certain predictors should be provided. Were clinically important variables forced into the model regardless of AIC?

4.Interpretation of Findings

- The prevalence of CVD (5%) appears low compared to regional estimates. Beyond underdiagnosis, could age distribution of the sample or exclusion of older adults (>69 years) contribute? This should be discussed.

- Country-specific differences (e.g., Uganda vs. Sudan) are reported but not adequately contextualized. Possible reasons (healthcare access, survey methodology differences, cultural factors) should be explored.

5.Treatment Uptake Analysis

-The analysis of CVD treatment uptake is valuable, but “treatment” is broadly defined (aspirin, statins, counseling). Were these self-reported or objectively verified? Please clarify.

- It would strengthen the manuscript to stratify treatment uptake by type of CVD (stroke vs. heart disease) if data permit.

6.Equity and Socioeconomic Status

- The manuscript acknowledges the lack of wealth quintile data. Could proxies (education, urban/rural status, occupation) be used to explore socioeconomic gradients in treatment uptake? This would add depth to the equity discussion.

7.Discussion Needs More Policy-Relevant Insights

- The discussion largely reiterates results. It would benefit from:

- Prioritizing interventions (e.g., integration of CVD care into primary care, task-shifting, low-cost drug provision).

- Comparing findings with other LMIC contexts (Asia, Latin America).

- Highlighting research gaps for future WHO STEPS iterations (e.g., inclusion of screening/care cascade data).

8. Abstract:

- Indicate clearly that CVD prevalence was self-reported.

- Include the sample size for those receiving prophylaxis (11% of 23,630).

9. Tables & Figures:

- Tables are dense. Consider moving some to supplementary files.

- Ensure consistent use of weighted vs. unweighted percentages.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

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Reviewer #1: Yes: Shukri M AlSaif

Reviewer #2: No

Reviewer #3: No

**********

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PLoS One. 2026 Mar 25;21(3):e0320276. doi: 10.1371/journal.pone.0320276.r002

Author response to Decision Letter 1


3 Oct 2025

Rebuttal Letter – PONE-D-25-08153

Title: The Prevalence, Prevention, and Treatment of Cardiovascular Diseases in Twelve African Countries (2014–2019): An Analysis of the World Health Organisation STEPwise Approach to Chronic Disease Risk Factor Surveillance

Dear Editors and Reviewers,

We sincerely thank the reviewers for their thoughtful and constructive feedback, which has greatly improved the clarity, rigor, and policy relevance of our manuscript. We have addressed all comments and provide a summary of our responses below.

Reviewer #1

• Africa vs. SSA: The manuscript has been revised to represent Africa rather than SSA.

• Exclusion statement: The sentence has been clarified to read: “We excluded 141,833 patients with missing CVD information.”

Reviewer #2

• Clarity and structure: Long paragraphs have been split, sub-sections for CVD prevalence, prevention, and treatment uptake were added, and key statistics summarized in tables and figures.

• Research gap: The introduction now clearly states the gap in multi-country analyses assessing the CVD care continuum in Africa.

• Imputation and methods: Detailed rationale for using simulation-based imputation (binomial, multinomial, Gaussian) has been added, including a comparison with complete-case analysis. The age cutoff of ≥40 years for “at risk” individuals is justified with references.

• Visuals: Bar plots and forest plots have been added for CVD prevalence, treatment, and prevention.

• Discussion: Sub-sections reduce redundancy; key findings and policy implications are emphasized.

• Limitations: Country-level health system indicators and potential diagnostic bias are now discussed.

• Technical edits: Language and grammar, consistency in terminology, and data reporting have been revised.

Reviewer #3

• Case definitions: The operational definition of CVD and the standardized WHO STEPS questions have been clarified in the abstract and discussion.

• Methodology: Missing data proportions, imputation rationale, and survey-weighted quasibinomial regression details have been included. Clinically important predictors (age, sex, hypertension) were retained based on AIC.

• Interpretation: Low CVD prevalence is contextualized by age distribution and exclusion of older adults; country-specific differences are noted, with suggestions for future qualitative analyses.

• Treatment uptake: Self-reported treatment and counselling measures clarified; stratification by CVD type not possible due to dataset limitations.

• Equity and socioeconomic status: Proxies (urban/rural residence, gender, education) were used; suggestions for future topic modeling and qualitative approaches incorporated.

• Policy relevance and care cascade: Discussion now prioritizes interventions (integration into primary care, task-shifting, low-cost drug provision), compares African findings with other LMICs (Asia, Latin America), and highlights gaps for future WHO STEPS surveys, including inclusion of screening and care cascade data. Only 11% of high-risk individuals received prevention therapy, and 22% of those with CVD received treatment, demonstrating substantial gaps.

• Abstract and figures: Weighted percentages clarified; sample sizes for prophylaxis included; tables and figures revised for clarity.

We believe these revisions substantially improve the manuscript’s clarity, methodological transparency, and relevance for policy and practice. We appreciate the reviewers’ guidance and hope the revised manuscript meets the standards for publication in PLOS ONE.

The detailed responses to each reviewer comments are presented below in bullet form under each key issue.

Thank you for your consideration.

Sincerely,

Wingston Ng’ambi, MSc Epidemiology

On behalf of all authors

Point-by-point response to review comments

Reviewer #1: Introduction and discussion sections talk on SSA but this study does include data from Morroco and Algiers and therefore not sure whether one should talk on SSA. The study represents Africa.

RESPONSE: This has been revised to represent Africa and not SSA

Line 121 to 123; please correct the statement. Those that were excluded were the 141833 patients that did not have information on CVD. please correct.

RESPONSE: We have added the sentence on line 126: We excluded 141,833 patients with missing CVD information.

Reviewer #2: 1. Clarity and Structure

The paper is dense in places. Consider improving the flow by: Splitting long paragraphs into digestible chunks. Adding section headers in the Results and Discussion for CVD prevalence, CVD prevention, and CVD treatment uptake to improve readability. Summarizing key stats in bulleted lists or tables where appropriate.

RESPONSE: This has been reviewed accordingly through introduction of the suggested sub-sections.

2. Introduction: Need for a Clearer Research Gap

While the introduction covers background well, it could more clearly state the specific gap this study addresses. Suggestion: “Despite the rising burden of CVDs in SSA, there is a lack of multi-country analyses assessing the full care continuum — from diagnosis to treatment — in this region.”

RESPONSE: The paper has been revised to reflect the African context and not the SSA. We have also made the gap clearer as recommended: Despite the growing prevalence of CVDs in Africa, there is a lack of multi-country analyses assessing the full care continuum; from diagnosis to treatment; in this region.

3. Methods: More Detail Needed

Imputation of Missing Data: More detail on the simulation approach used (binomial, multinomial, Gaussian) would help replicate or critique the methodology. Why was this approach chosen over multiple imputation or complete-case analysis? Definition of ‘At Risk’ Individuals: You define “at risk” as ≥40 years old. Justify this age cutoff more explicitly with references or explain why this was chosen over risk factor-based definitions.

RESPONSE: The previous version of the paper already included the reference for selection of those of ≥40 years as being at risk: In order to ascertain the uptake of CVD prevention therapy, all the individuals aged at least 40 years were considered to be at risk of CVD and this formed the denominator for this analysis [24].

As for the simulation; we have added more details as shown below: Imputation was performed to handle the missing data because it allows for the inclusion of all available data in the analysis, ensuring more accurate and representative results. Different probability distributions were specified depending on the type of variable. For binary variables, such as presence or absence of a condition, we used a binomial distribution. For categorical variables with more than two groups, such as education level or occupation, we applied a multinomial distribution. For continuous variables, including age, body mass index, and blood pressure, a Gaussian distribution was used. These simulation models were implemented using random assignment based on the observed distribution of each variable, ensuring that imputed values reflected the empirical patterns in the data. This strategy allowed us to approximate the underlying data-generating mechanism more realistically, reduce bias from listwise deletion, and retain the full analytic sample.

4. Results: More Visuals Could Help. Consider including: A map showing prevalence of CVD by country. Bar plots or forest plots for adjusted odds ratios.

RESPONSE: We have presented the bar plots for the CVD care (prevalence, treatment and prevention) by country. We have also presented the forest plots for each of the multi-variable analyses for CVD prevention, CVD prevalence and CVD treatment.

5. Discussion: Slight Redundancy. Some points in the discussion (e.g., treatment disparities by gender, hypertension as a CVD risk) are repeated across several paragraphs. Try to consolidate and avoid redundancy.

RESPONSE: These refer to CVD prevalence, CVD prevention and CVD treatment. We have added the sub-sections to ensure that the discussion is less confusing and clearer.

6. Limitations: A Few More Could Be Added. The study doesn't account for country-level health system indicators (e.g., availability of aspirin or statins, national NCD strategies), which could partly explain inter-country differences. There may be diagnostic bias due to self-reported CVD, especially in settings where people have less access to healthcare.

RESPONSE: Thanks for pointing this out. We have included this in the limitations: First, the analysis did not incorporate country-level health system indicators, such as the availability of essential medicines (e.g., aspirin or statins) or the existence of national NCD strategies, which may partly explain inter-country differences.

7. Technical and Stylistic Suggestions

- Language & Grammar:Replace awkward or redundant phrasing: "the CVD cases from Sudan had the highest..." ➜ "CVD cases in Sudan showed the highest treatment uptake..." “an individual with hypertension were” ➜ “individuals with hypertension were”

RESPONSE: We have revised the grammar as pointed out by the reviewers.

- Consistency:

Use either "sub-Saharan Africa (SSA)" or "SSA" consistently. Be consistent in using "CVD prevention" vs "CVD prophylaxis" — stick to one term.

RESPONSE: The context has been changed to Africa. The paper has also focused on CVD prevention.

- Data Reporting: Some statistics could be presented more concisely: Example: "Of the 23,630 persons at risk of CVD, 11% received prophylaxis or counselling." You could split this to say: “Only 11% received any form of prophylaxis or counselling, highlighting a major prevention gap.”

RESPONSE: This has been revised accordingly

Reviewer #3: This manuscript addresses a critical public health issue—cardiovascular disease (CVD) prevalence, prevention, and treatment in sub-Saharan Africa—using WHO STEPS data. The multi-country scope and large sample size are notable strengths, and the topic aligns well with the journal’s readership. However, the manuscript would benefit from clearer methodological details, improved interpretation of findings, and refinement of the discussion to provide more actionable policy insights.

1.Clarity on Case Definitions

- The operational definition of “CVD” in this study is based on self-reported history of heart attack, angina, or stroke. This should be emphasized as a major limitation in the abstract and discussion. It may underestimate the true prevalence of CVD due to lack of diagnostic confirmation.

RESPONSE: This has been reflected in the abstract and limitation sections of the paper. CVD was defined as a self-reported history of heart attack, angina, or stroke. The actual question adapted from the WHO STEPS is: “Have you ever had a heart attack, angina (chest discomfort caused by heart disease), or stroke (cerebrovascular accident or incident)?”. The limitation has included the CVD: Second, the study relied on self-reported information regarding heart attacks, CVD treatment, and related risk and protective factors. This approach may introduce diagnostic and recall bias, particularly in settings with limited healthcare access, where individuals may be unaware of or unable to accurately report their condition or treatment history. These factors should be considered when interpreting the results and may provide avenues for future research. We were, however, unable to estimate the extent of underestimation or overestimation of the reported CVD-related risk and protective factors with heart attack and CVD treatment uptake.

- Please clarify whether “angina” was assessed by standardized questions (e.g., Rose questionnaire) or a single self-report item.

RESPONSE: This was based on a standardised question from WHO NCD STEPS: “Have you ever had a heart attack, angina (chest discomfort caused by heart disease), or stroke (cerebrovascular accident or incident)?”

2.Methodological Details

- The imputation strategy is briefly described (binomial, multinomial, Gaussian simulations). Please elaborate on:

The proportion of missing data for each variable.

RESPONSE: A figure for the missingness of data for each variable before imputation has been included. Overall, 26% of the individuals had missing data. We have also added Box 1 for the proportion of missing data for each of the variables.

Box 1: Proportion of missing data across variables used to assess cardiovascular disease prevalence in twelve African countries, 2014–2019

Justification for using simulation instead of standard MICE approaches (beyond the “autocorrelation” statement).

RESPONSE: We opted for simulation-based imputation instead of standard MICE approaches for several reasons. First, the data exhibited complex patterns across multiple countries, including high inter-variable correlations and heterogeneity in variable distributions, which led to convergence issues and unstable chains when using MICE. Second, some variables had non-standard distributions or rare categories that are not easily handled by default MICE models. Third, simulation-based imputation allows direct specification of the appropriate distribution for each variable type (binomial, multinomial, Gaussian), ensuring that imputed values reflect the empirical distribution of the observed data. Finally, this approach avoids the iterative dependency structure of MICE, which can amplify biases in the presence of autocorrelation, while preserving sample size and statistical power.

Sensitivity analyses to assess robustness of imputation assumptions.

RESPONSE: Sensitivity analyses were conducted to assess the robustness of the imputation assumptions by comparing results from the simulation-based imputation to a complete case analysis. This approach evaluated whether the main findings were influenced by the distributional assumptions used for imputing missing values as shown in Box 2.

Box 2: Sensitivity analysis of determinant coefficients for cardiovascular disease prevalence, comparing imputation and complete case analysis in twelve African countries, 2014–2019

The use of weighted logistic regression is appropriate, but details of how survey weights were incorporated into multivariable models should be expanded.

We have added further details: The quasibinomial distribution, an extension of the standard binomial distribution, is particularly suitable for survey data with binary outcomes, as it accounts for overdispersion. For each survey-weighted multivariable quasibinomial logistic regression model, survey weights were incorporated directly into the model fitting to ensure that parameter estimates reflected the complex sampling design. Weighted standard errors were calculated to account for unequal selection probabilities, thereby producing valid confidence intervals and p-values. We first fitted a full model including all candidate predictors and then applied backward variable selection using the stepAIC function from the MASS R package, retaining predictors that optimized model fit while respecting the survey weights.

3.Selection of Predictor Variables

- The stepwise selection via AIC is described, but a rationale for retaining or excluding certain predictors should be provided. Were clinically important variables forced into the model regardless of AIC?

RESPONSE: This has been further clarified as follows: The stepAIC function was used for stepwise selection, optimizing model fit by retaining predictors that minimized the AIC. Notably, the clinically important variables; age, sex, and hypertension status; were naturally retained in the final model based on the AIC criterion, so no variables needed to be forced into the model.

4.Interpretation of Findings

- The prevalence of CVD (5%) appears low compared to regional estimates. Beyond underdiagnosis, could age distribution of the sample or exclusion of older adults (>69 years) contribute? This should be discussed.

RESPONSE: The discussion has included the exclusion of the persons >69 who are reported to have higher CVD risk and prevalence. Here is part of the extract incorporating the feedback: The overall CVD prevalence of 5% in this study was consistent with findings from a meta-analysis that found the CVD prevalence to be 7% in SSA [29]. In contrast, other regions exhibit higher CVD prevalence, for example,

Decision Letter 1

Muhammad Farooq Umer

18 Nov 2025

Dear Dr.  Ng'ambi,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Jan 02 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Muhammad Farooq Umer, PhD Epidemiology and Health Statistics

Academic Editor

PLOS ONE

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1. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

2. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

There still remains some key issues to be resolved, please carefully revise the manuscript in the light of comments from the reviewer.

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Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #1: Yes

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: I Don't Know

Reviewer #3: I Don't Know

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #3: Yes

**********

Reviewer #1: all the points that I have raised in the previous version have been adequately addressed and corrected.

Reviewer #3: This revised manuscript addresses an important and underexplored topic, the continuum of cardiovascular disease (CVD) care in African countries using the WHO STEPS dataset. The authors have made substantial efforts to improve the clarity, structure, and methodological transparency in response to prior reviewer feedback. The revision provides clearer definitions, expanded methodological justifications, improved discussion, and a better visual presentation of findings. The manuscript now reads more coherently and aligns more closely with PLOS ONE’s standards of scientific rigor and reproducibility.

Nevertheless, a few issues remain that, if addressed, would further enhance the scientific robustness and policy relevance of the paper.

1. Methodological Transparency and Reproducibility

- The authors have elaborated on the simulation-based imputation approach, but the reproducibility of the method remains somewhat limited. It would be helpful to specify:

- The exact R functions or packages used for each distributional simulation.

- Whether random seeds were set for reproducibility.

- A brief note on convergence diagnostics or distributional checks to ensure the plausibility of imputed values.

- Consider including the code snippet or workflow for the imputation procedure as a supplementary file to support transparency and reproducibility.

2.Survey Weighting and Model Specification

- The authors correctly used a quasibinomial model with survey weights; however, it is unclear whether the design variables (e.g., strata, PSU) were incorporated. Clarify whether svydesign or equivalent functions were used to define the complex design prior to regression.

- It would also be valuable to explicitly mention whether inter-country clustering was accounted for (fixed vs. random effects).

3. Interpretation of Results

- While the discussion of cross-country variation is improved, the manuscript still tends to attribute differences mainly to healthcare access and diagnostic capabilities. Including limited contextual references (e.g., national NCD programs or WHO PEN implementation status) could strengthen this argument.

- The term “care cascade” is used effectively, but its operational definition could be more precise (diagnosis, treatment, and counselling as sequential stages). Presenting this in a conceptual diagram would enhance comprehension.

4. Equity and Socioeconomic Gradients

- The inclusion of proxies (education, rural/urban residence, sex) is appreciated. Consider presenting an additional table or figure (e.g., forest plot) that explicitly compares adjusted odds ratios for these equity variables in both prevention and treatment models.

- The discussion could better emphasize the policy implications of these equity findings, particularly the urban–rural and gender gaps.

5.Presentation and Figures

- Figures are clearer, yet some remain dense. Consider simplifying the forest plots by separating prevalence, prevention, and treatment results into distinct panels or supplementary figures.

- In the abstract and results, please ensure that all percentages are clearly stated as weighted, and that denominators are explicitly defined for each statistic.

6.Limitations

- The authors have acknowledged self-report bias and missing health system indicators. However, the limitation regarding temporal heterogeneity (different survey years from 2014–2019) should be mentioned explicitly, as CVD risk profiles and treatment policies may have evolved during that period.

7. Line editing: Ensure consistent use of terms — e.g., “CVD prevention therapy” vs. “CVD prophylaxis” (the revision appears mostly consistent but should be rechecked).

8. The acronym “WHO STEPS” should be expanded once in the abstract and once in the main text, followed by consistent use thereafter.

9. Provide brief country-level context (perhaps in Supplementary Table) such as survey year, sample size, and population coverage to aid interpretation.

10. Ensure all figures and tables have self-contained legends that allow standalone interpretation.

**********

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Reviewer #1: No

Reviewer #3: No

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PLoS One. 2026 Mar 25;21(3):e0320276. doi: 10.1371/journal.pone.0320276.r004

Author response to Decision Letter 2


29 Nov 2025

Reviewer #1: all the points that I have raised in the previous version have been adequately addressed and corrected.

RESPONSE: We thank the reviewer for acknowledging our revisions and are pleased that all previously raised concerns have been satisfactorily addressed.

Reviewer #3: This revised manuscript addresses an important and underexplored topic, the continuum of cardiovascular disease (CVD) care in African countries using the WHO STEPS dataset. The authors have made substantial efforts to improve the clarity, structure, and methodological transparency in response to prior reviewer feedback. The revision provides clearer definitions, expanded methodological justifications, improved discussion, and a better visual presentation of findings. The manuscript now reads more coherently and aligns more closely with PLOS ONE’s standards of scientific rigor and reproducibility.

Nevertheless, a few issues remain that, if addressed, would further enhance the scientific robustness and policy relevance of the paper.

RESPONSE: We thank Reviewer #3 for their thoughtful and constructive assessment of our revised manuscript. We appreciate the recognition of the improvements made regarding methodological clarity, structure, and the overall coherence of the paper. We have carefully considered the remaining issues highlighted and have now addressed each point comprehensively in the current revision. Specifically, we have refined the operational definition of the CVD care cascade, expanded contextual explanations for cross-country variation, clarified the simulation-based imputation approach, and strengthened the discussion of equity-related findings and their policy implications. We believe that these additional revisions further enhance the scientific robustness, clarity, and policy relevance of the manuscript, and we appreciate the reviewer’s role in helping improve the quality of this work.

1. Methodological Transparency and Reproducibility

- The authors have elaborated on the simulation-based imputation approach, but the reproducibility of the method remains somewhat limited. It would be helpful to specify:

- The exact R functions or packages used for each distributional simulation.

- Whether random seeds were set for reproducibility.

- A brief note on convergence diagnostics or distributional checks to ensure the plausibility of imputed values.

RESPONSE: We appreciate the reviewer’s concern regarding reproducibility of the simulation-based imputation procedure. To enhance clarity, we provided additional details below. For the imputation of categorical variables, we used the base R function sample(), drawing from the observed distribution of each variable to probabilistically populate missing values. For continuous variables such as age, we simulated values using the observed mean and standard deviation, generating draws from a normal distribution via rnorm(), after which we converted the simulated values to integers to reflect the natural scale of the variable.

To support reproducibility, we set a random seed (using set.seed()) prior to running the imputation procedure. We also performed basic distributional checks by comparing the empirical distribution of imputed values with that of the complete cases to ensure plausibility and consistency. Since the approach relied on direct simulation rather than iterative model-based imputation, traditional convergence diagnostics were not applicable; however, we assessed the stability of results by repeating the simulation multiple times and confirming that no material differences occurred.

- Consider including the code snippet or workflow for the imputation procedure as a supplementary file to support transparency and reproducibility.

RESPONSE: We appreciate the suggestion; however, the simulation procedure used for imputation was a straightforward application of basic R functions (e.g., sample() and rnorm()) and did not involve a complex or multi-step workflow. Given its simplicity, we believe that including a supplementary code file is not essential, though we remain open to providing additional details upon request.

2.Survey Weighting and Model Specification

- The authors correctly used a quasibinomial model with survey weights; however, it is unclear whether the design variables (e.g., strata, PSU) were incorporated. Clarify whether svydesign or equivalent functions were used to define the complex design prior to regression.

- It would also be valuable to explicitly mention whether inter-country clustering was accounted for (fixed vs. random effects).

RESPONSE: We set up the survey design before fitting any models and used the same weight variable, wstep1, throughout the analysis. For the CVD prevalence and prevention datasets, we defined a full complex design using psu as the cluster, stratum as the stratification variable, and wstep1 as the sampling weight, with nesting enabled. For the treatment dataset, only wstep1 was available, so we applied a simple one stage design. All quasibinomial models for CVD prevalence were run on these survey design objects, ensuring that the sampling structure was properly accounted for. We also adjusted for inter country variation by including country fixed effects, rather than treating countries as random clusters. This allowed us to capture differences across countries in a clear and consistent way.

3. Interpretation of Results

- While the discussion of cross-country variation is improved, the manuscript still tends to attribute differences mainly to healthcare access and diagnostic capabilities. Including limited contextual references (e.g., national NCD programs or WHO PEN implementation status) could strengthen this argument.

RESPONSE: Thank you for this valuable suggestion. We have revised the discussion to broaden our explanation of cross-country variation by incorporating contextual factors beyond healthcare access and diagnostic capacity. Specifically, we now refer to differences in the implementation of national NCD programmes, the varying rollout of WHO PEN interventions, and other contextual influences that may shape CVD prevalence and management across countries. These additions strengthen the argument and provide a more comprehensive interpretation of the observed geographic variations.

- The term “care cascade” is used effectively, but its operational definition could be more precise (diagnosis, treatment, and counselling as sequential stages). Presenting this in a conceptual diagram would enhance comprehension.

RESPONSE: Our analysis is structured around the CVD care pathway; spanning diagnosis, treatment initiation, and counselling/adherence support; which provides a systematic framework to identify gaps in care and is particularly relevant in the African context, where resource constraints and variations in health system capacity can lead to substantial drop-offs at each stage of the cascade (see Box 3). We have added the care pathway conceptual framework and called it (Box 3). The conceptual framework is shown below.

4. Equity and Socioeconomic Gradients

- The inclusion of proxies (education, rural/urban residence, sex) is appreciated. Consider presenting an additional table or figure (e.g., forest plot) that explicitly compares adjusted odds ratios for these equity variables in both prevention and treatment models.

- The discussion could better emphasize the policy implications of these equity findings, particularly the urban–rural and gender gaps.

RESPONSE: We appreciate the reviewer’s suggestion. The adjusted associations for equity-related variables (education, rural/urban residence, and sex) are already presented in the forest plots included in the main manuscript, providing a clear comparison across prevention and treatment models. Additionally, the discussion section already addresses the policy implications of these findings, including urban–rural and gender disparities, in detail.

5.Presentation and Figures

- Figures are clearer, yet some remain dense. Consider simplifying the forest plots by separating prevalence, prevention, and treatment results into distinct panels or supplementary figures.

RESPONSE: The figures are already separated based on the previous submission and comments from the reviewers.

- In the abstract and results, please ensure that all percentages are clearly stated as weighted, and that denominators are explicitly defined for each statistic.

RESPONSE: The denominators were defined clearly. For each percentage, we have provided the corresponding number of events (i.e. the numerator), especially amongst those receiving treatment. The methods section of the abstract explicitly states that the percentages are all weighted.

6.Limitations

- The authors have acknowledged self-report bias and missing health system indicators. However, the limitation regarding temporal heterogeneity (different survey years from 2014–2019) should be mentioned explicitly, as CVD risk profiles and treatment policies may have evolved during that period.

RESPONSE: We thank the reviewer for this insightful comment. While we recognize that the surveys span different years (2014–2019) and that CVD risk profiles and treatment policies may have evolved, each country contributed only a single survey in our analysis, and the variable for survey year was not statistically significant. We have clarified this limitation in the manuscript. We hope that future analyses with additional data across multiple time points in Africa will allow for the evaluation of temporal trends, making the year variable more meaningful as you suggest.

7. Line editing: Ensure consistent use of terms — e.g., “CVD prevention therapy” vs. “CVD prophylaxis” (the revision appears mostly consistent but should be rechecked).

RESPONSE: We thank the reviewer for the suggestion. We have carefully checked the manuscript and ensured consistent use of terminology, using “CVD prevention therapy” throughout.

8. The acronym “WHO STEPS” should be expanded once in the abstract and once in the main text, followed by consistent use thereafter.

RESPONSE: We thank the reviewer for this comment. “WHO STEPS” has now been expanded to “World Health Organization STEPwise Approach to Surveillance (WHO STEPS)” once in the abstract and once in the main text, and we have ensured consistent use of the acronym throughout the manuscript.

9. Provide brief country-level context (perhaps in Supplementary Table) such as survey year, sample size, and population coverage to aid interpretation.

Response: We have added this Box 1 in the paper.

Box 1: WHO STEPWise Surveys with cardiovascular disease data in African countries: 2014-2019

Country Sub-region

in Africa Survey year Sample size

Algeria Northern 2016 6,955

Benin Western 2015 5,115

Botswana Southern 2014 3,888

Eswatini Southern 2014 3,026

Ethiopia Eastern 2015 9,241

Kenya Eastern 2015 4,477

Malawi Eastern 2017 4,186

Morocco Northern 2017 4,991

Sao Tome and Principe Central 2019 2,418

Sudan Northern 2016 7,722

Uganda Eastern 2014 3,973

Zambia Eastern 2017 4,302

Total 60,294

10. Ensure all figures and tables have self-contained legends that allow standalone interpretation.

RESPONSE: We thank the reviewer for this suggestion. All figures and tables have been reviewed and now include self-contained l

Decision Letter 2

Muhammad Farooq Umer

8 Dec 2025

Dear Dr. Ng'ambi,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please address each comment individually and in detail in a separate response document. Where revisions are feasible and consistent with your study objectives, we encourage you to incorporate them into the manuscript.

If you encounter any reviewer requests that you believe are beyond the reasonable scope of the current study, you may provide a clear and logical explanation in your response. It is acceptable to justify why certain suggested analyses or additions cannot be carried out at this stage. In such cases, please ensure that the manuscript transparently acknowledges the relevant limitations.

Please proceed with the revision while maintaining clarity, scientific rigor, and alignment with the study’s original scope. We look forward to receiving your updated manuscript and response to reviewers.

Please submit your revised manuscript by Jan 22 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Muhammad Farooq Umer, PhD Epidemiology and Health Statistics

Academic Editor

PLOS One

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #3: Yes

**********

Reviewer #3: The authors have substantially strengthened the manuscript, improving clarity, methodological transparency, and alignment with PLOS ONE requirements. The study addresses an important gap by providing a multi-country analysis of CVD prevalence, prevention, and treatment across 12 African nations using WHO STEPS data. The revisions improve the conceptual framing of the care cascade, incorporate methodological clarifications, and address prior reviewer suggestions. Overall, the work is valuable, but several areas still require refinement before publication.

1. Conceptual Framework of the CVD Care Cascade

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- The framework still appears loosely defined, especially regarding how “diagnosis,” “treatment,” and “counselling” are operationalized within STEPS constraints.

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- As STEPS lacks screening and clinical verification variables, the authors should explicitly explain how “diagnosis” was inferred purely from self-report and discuss potential misclassification bias more prominently in the limitations.

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- The care cascade figure would benefit from clear denominators, especially when presenting drop-off proportions.

2. Methodological Transparency

The authors provide additional detail on simulation-based imputation; however:

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- The explanation remains narrative rather than fully reproducible. PLOS ONE strongly encourages reproducible workflows.

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- Even if the code is simple, a minimal code snippet in Supplementary Material would strengthen transparency and address reviewer concerns.

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- It should also be made clear how country stratification affects the imputation procedure, since distributions may vary substantially across countries.

3. Survey Design and Regression Modelling

The description of survey weighting is improved, but two issues require clarification:

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- For treatment data, where only weights were available:

→ Please discuss how the absence of PSU and strata may affect standard errors and whether sensitivity analyses were performed.

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- Country fixed effects were included; however, given the heterogeneity in sample sizes and survey years, authors should discuss whether mixed-effect modeling was considered and why it was not preferred.

4. Interpretation of Geographic Variation

While country-level context has been expanded, interpretation remains somewhat descriptive:

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- The manuscript should incorporate specific examples of national NCD strategies or PEN implementation status (even 1–2 sentences per region), rather than broad statements.

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- Some contextual explanations appear speculative without supporting references (e.g., differences attributed to “cultural practices”). Please add citations or revise language.

5. Use of Weighted Percentages in Results and Abstract

Percentages in several places (e.g., prevalence 5%, prevention uptake 11%, treatment 22%) continue to lack explicit denominators or confirmation of whether they are weighted.

PLOS ONE requires full clarity here. Please:

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- ensure all percentages are described as weighted in each relevant section,

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- provide “weighted %, unweighted n/N” whenever possible.

6. Overinterpretation of Self-Reported CVD

Because all CVD diagnoses are self-reported:

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- There is risk of both under-reporting (low diagnostic access) and over-reporting (misunderstanding of medical terminology).

The addition of a conceptual framework (Box 3) improves the manuscript; however:

- The discussion should more fully address how this impacts cross-country comparisons and potential bias in associations.

7. Language and Consistency

- Some terminology remains inconsistent, e.g., “treatment or counselling” vs. “treatment and counselling”; “CVD prevention therapy” vs. “preventive therapy.”

A final consistency check is recommended.

8. Figures and Tables

- Several forest plots remain very dense. Splitting into prevalence / prevention / treatment panels (or moving some to Supplement) may improve readability.

- Ensure all legends are fully self-contained (PLOS ONE requirement).

9. Limitations Section

- The new text addressing temporal heterogeneity is appreciated; however, the rationale (“only one survey per country”) does not fully negate temporal implications, because survey years differ by up to 5 years.

A more explicit acknowledgement would strengthen the transparency.

10. Country-Level Table (Box 1)

- This is a valuable addition.

Consider adding survey type (STEPS 1/2/3 coverage) since countries differ in biochemical testing coverage, which affects predictive variables.

11. Justification for Age ≥40 Threshold

- Although aligned with WHO STEPS guidelines, please cite additional evidence supporting the ≥40 cutoff for defining CVD risk groups across African populations.

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Reviewer #3: No

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PLoS One. 2026 Mar 25;21(3):e0320276. doi: 10.1371/journal.pone.0320276.r006

Author response to Decision Letter 3


26 Jan 2026

Manuscript ID: PONE-D-25-08153R2

Manuscript ID: PONE-D-25-08153R2

Title: The Prevalence, Prevention, and Treatment of Cardiovascular Diseases in Twelve African Countries (2014–2019): An Analysis of the World Health Organisation STEPwise Approach to Chronic Disease Risk Factor Surveillance

Journal: PLOS ONE

________________________________________

Response to the Academic Editor and Reviewer #3

Dear Dr. Umer,

Dear Reviewer #3,

We sincerely thank the Academic Editor and Reviewer #3 for their careful evaluation of our revised manuscript and for the constructive, detailed feedback provided during this review round. We are encouraged by the reviewer’s assessment that the manuscript has been substantially strengthened and now demonstrates improved clarity, methodological transparency, and alignment with PLOS ONE requirements.

We have carefully addressed all remaining comments and have further revised the manuscript to enhance conceptual clarity, transparency, and interpretability, while remaining within the scope and analytical constraints of the WHO STEPS dataset. All changes have been highlighted in the tracked-changes version of the manuscript.

Below, we provide a point-by-point response to each comment raised by Reviewer #3. Reviewer comments are reproduced in italicized text, followed by our responses.

________________________________________

Reviewer #3 Comments and Responses

1. Conceptual Framework of the CVD Care Cascade

The framework still appears loosely defined, especially regarding how “diagnosis,” “treatment,” and “counselling” are operationalized within STEPS constraints. As STEPS lacks screening and clinical verification variables, diagnosis should be clearly described as self-reported, and misclassification bias more prominently discussed. The care cascade figure would benefit from clear denominators.

Response:

We thank the reviewer for this valuable feedback. We have revised Box 3 (Conceptual Framework) to explicitly define how diagnosis, treatment, and counselling are operationalized using self-reported variables available in WHO STEPS. We now clearly state that STEPS does not include clinical screening or diagnostic verification, and that the diagnosis stage reflects respondents’ self-reported prior diagnosis or awareness of elevated blood pressure or glucose.

We have also expanded the Limitations section to more prominently discuss potential misclassification and recall bias arising from reliance on self-reported data. In addition, the care cascade figure and accompanying text now clearly indicate that all cascade estimates use conditional denominators, with each stage defined relative to the preceding stage, to improve interpretation of drop-off proportions.

________________________________________

2. Methodological Transparency and Reproducibility

The explanation of simulation-based imputation remains narrative rather than fully reproducible. A minimal code snippet in the Supplementary Material would strengthen transparency. It should also be clear how country stratification affects the imputation procedure.

Response:

We appreciate this important suggestion. To enhance reproducibility, we have now included minimal, fully reproducible R code snippets in the Supplementary Material, illustrating the simulation-based imputation of both discrete variables (e.g., sex, smoking status, physical activity, harmful alcohol use) and continuous variables (e.g., age, BMI, cholesterol). All examples include fixed random seeds and reflect the exact procedures used in the analysis.

We also explicitly clarify in the Methods that imputation was conducted on pooled multi-country data, rather than within individual countries. Replacement values were therefore drawn from overall empirical distributions. We acknowledge that this approach does not capture country-specific heterogeneity in risk factor distributions, and this limitation is now clearly stated in both the Methods and the Limitations sections. Additionally, all analysis code has been made available in the supplementary code folder to enable full replication of the workflow.

________________________________________

3. Survey Design and Regression Modelling

For treatment analyses, only weights were available. Please discuss how the absence of PSU and strata may affect standard errors and whether sensitivity analyses were performed. Also, justify the use of country fixed effects rather than mixed-effects models.

Response:

All analyses were conducted using survey weights to account for unequal probabilities of selection. For treatment-related analyses, only individual-level weights were available. Primary sampling units (PSUs) and strata could not be incorporated because their inclusion resulted in errors during survey object specification in the pooled, harmonized dataset. As a result, variance estimates may be underestimated, and confidence intervals potentially overly narrow. We did not conduct formal sensitivity analyses comparing alternative survey specifications, and this is now explicitly acknowledged as a limitation in the Discussion.

Country fixed effects were included to control for unobserved, time-invariant country-level differences. While mixed-effects models were considered, they were not preferred due to substantial heterogeneity in survey years, sample sizes, and survey design characteristics, as well as computational instability when combining multilevel modeling with weighted survey data. Given our primary objective of estimating average associations across countries, fixed-effects models were deemed more appropriate. This rationale is now clarified in the Methods and discussed in the Limitations section.

________________________________________

4. Interpretation of Geographic Variation

Interpretation remains somewhat descriptive. Please include concrete examples of national NCD strategies or PEN implementation and ensure that contextual explanations are supported by references.

Response:

We thank the reviewer for this suggestion. We have added a dedicated PEN implementation subsection in the Methods, providing specific country- and region-level examples of national NCD strategies and WHO PEN adoption. We also reviewed all contextual interpretations to ensure they are supported by appropriate references. Where empirical evidence was limited, the language has been revised to remain descriptive rather than speculative. Relevant citations have been added or clarified accordingly.

________________________________________

5. Use of Weighted Percentages and Denominators

Percentages lack explicit confirmation that they are weighted, and PLOS ONE requires clarity on denominators.

Response:

We have revised the Abstract and Results to clearly state that all reported percentages are weighted estimates derived from complex survey data. Denominators have been clarified where applicable. While we considered presenting both weighted percentages and unweighted counts (n/N), we opted to present weighted estimates only to maintain clarity and avoid confusion, as weighted values are most appropriate for population-level inference from STEPS data. This choice is now clearly stated in the Methods.

________________________________________

6. Overinterpretation of Self-Reported CVD

There is risk of both under- and over-reporting. The discussion should more fully address implications for cross-country comparisons and potential bias in associations.

Response:

We agree with this concern. We have added a new paragraph immediately before the Strengths and Limitations section that explicitly discusses how reliance on self-reported CVD diagnosis may influence cross-country comparisons and introduce differential misclassification, particularly in settings with variable access to diagnostic services. We also discuss how this limitation may bias observed associations.

________________________________________

7. Language and Terminology Consistency

Some terminology remains inconsistent.

Response:

We conducted a full manuscript consistency check and standardized terminology throughout (e.g., “treatment and counselling,” “preventive therapy”). These issues have been resolved.

________________________________________

8. Figures and Tables

Forest plots are dense; consider splitting panels and ensure legends are self-contained.

Response:

Forest plots are now clearly organized into prevalence, prevention, and treatment panels, and all figure legends have been revised to be fully self-contained, with all abbreviations defined, in accordance with PLOS ONE requirements.

________________________________________

9. Limitations: Temporal Heterogeneity

The rationale does not fully negate temporal implications given survey year variation.

Response:

We have revised the Limitations section to explicitly acknowledge residual temporal heterogeneity arising from differences in survey years across countries. The revised text now notes that although survey year was not significantly associated with CVD risk, such heterogeneity may still influence between-country comparisons.

________________________________________

10. Country-Level Table (Box 1)

Consider adding STEPS 1/2/3 coverage.

Response:

We confirm that all included countries had STEPS 1, 2, and 3 coverage during the 2014–2019 period. This clarification has been added to Box 1.

________________________________________

11. Justification for Age ≥40 Threshold

Please provide additional evidence supporting the ≥40 cutoff in African populations.

Response:

We have added five additional references supporting the ≥40-year threshold, consistent with WHO guidance and evidence from African populations, and cited them in the Methods and Discussion.

________________________________________

Closing Statement

Once again, we thank the Academic Editor and Reviewer #3 for their thoughtful and constructive feedback. We believe that these revisions have further strengthened the manuscript’s rigor, transparency, and interpretability, while maintaining alignment with the study’s original objectives and the constraints of the WHO STEPS data.

We respectfully submit this revised manuscript for reconsideration and look forward to your decision.

Sincerely,

Wingston Felix Ng’ambi, MSc

(On behalf of all authors)

Decision Letter 3

Muhammad Farooq Umer

27 Jan 2026

The Prevalence, Prevention, and Treatment of Cardiovascular Diseases in Twelve African Countries (2014-2019): An Analysis of the World Health Organisation STEPwise Approach to Chronic Disease Risk Factor Surveillance

PONE-D-25-08153R3

Dear Dr. Ng'ambi,

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Kind regards,

Muhammad Farooq Umer, PhD Epidemiology and Health Statistics

Academic Editor

PLOS One

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Reviewers' comments:

Acceptance letter

Muhammad Farooq Umer

PONE-D-25-08153R3

PLOS One

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Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 File. 1_Create_dataset_for_analysis.

    R R script used to generate the dataset for analysis.

    (ZIP)

    pone.0320276.s001.zip (38.7KB, zip)
    S2 File. Sample simulation code.

    (DOCX)

    pone.0320276.s002.docx (15.4KB, docx)

    Data Availability Statement

    The data used in this study may be accessed at https://extranet.who.int/ncdsmicrodata/index.php/catalog/629.


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