May Measurement Month 2022: an analysis of blood pressure screening results from Kenya

Abstract

Hypertension is the largest contributor to the burden of disease globally, but awareness, treatment, and control rates remain low. In response to this, the annual global May Measurement Month (MMM) campaign was initiated by the International Society of Hypertension in 2017. This paper summarizes the results of the 2022 MMM campaign in Kenya. Adults aged ≥18 years were recruited across eight counties in Kenya. Three seated blood pressure (BP) readings were taken for each participant, along with completion of a questionnaire on demographics, lifestyle factors, and comorbidities. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg or being on antihypertensive medication. Controlled BP was defined as being on antihypertensive medication with a BP <140/90 mmHg. Multiple imputation was used to estimate any missing BP readings. In total, 9605 were screened, with a mean age of 43.0 years, 43.9% females and 3406 (35.5%) for the first time. Of all participants, 3167 (33.0%) had hypertension, of whom 982 (31.0%) were aware, and 936 (29.6%) were on antihypertensive medication. Of those on antihypertensive medication, 346 (37.0%) had controlled BP, and of all participants with hypertension, 10.9% had controlled BP. Of those on medication, the majority were on two (517; 55.2%) antihypertensive medication classes. The campaign identified significant numbers of participants with either untreated or inadequately treated hypertension. Hypertension control remains alarmingly low necessitating critical evaluation of possible contributors, including awareness and treatment optimization.

Introduction

Raised blood pressure (BP) is one of the largest contributors to the global burden of disease.¹ It is estimated that three-quarters of the total number of people living with hypertension globally reside in low-and middle-income countries.² The prevalence of hypertension in sub-Saharan Africa is on the rise, with 34% of men and 48% of women estimated to be hypertensive.² Despite the availability of effective medical and behavioural interventions and clinical guidelines, hypertension awareness, treatment, and control remain alarmingly low.² According to the World Health Organization (WHO) global report on hypertension, only 54% of adults with hypertension are diagnosed, 42% are on treatment and 21% are controlled.³ In a recent nationwide survey in Kenya using the WHO STEPs survey tool, the prevalence of hypertension was 24% with only 15.6% being aware, only 26.9% of those aware were on treatment, out of whom only 51.7% were controlled.⁴

May Measurement Month (MMM) was initiated in 2017 by the International Society of Hypertension and has since run annually, except for 2020 due to the COVID-19 pandemic. In 2022, the MMM campaign continued, with the aim of continuing to raise awareness of the dangers of raised BP and included 757 350 participants worldwide.⁵

Kenya participated in MMM in 2017, 2018, 2019, and 2021.^6-9 Findings from these campaigns have reported an increase in the proportion of those screened who were hypertensive from 24.7% in 2017⁵ to 28.2% in 2021.⁸ In addition, the proportion of those aware of their hypertension status, those on medication and overall BP control rates has progressively increased showing a positive trend in hypertension management. In this paper, we report on the findings of the MMM22 campaign in Kenya.

Methods

MMM is a cross-sectional opportunistic survey of consenting adults aged 18 years or over. The programme in Kenya was coordinated by Kenya Cardiac Society over the months of June to August 2022. Screening sites were set up in health facilities, religious gatherings, workplaces, and public spaces such as marketplaces and commuter stations across eight counties in Kenya. Screening was conducted by health professionals and volunteers who received virtual trainings on BP measurement and data collection. The campaign was advertised via social media and community mobilization by the volunteers.

In accordance with the standard MMM protocol, participants ideally had three seated BP readings measured at 1-min intervals, using standard procedures.⁵ Calibrated Omron M3 digital BP measurement devices were used. A questionnaire was also completed, collecting information on demographics, comorbidities, lifestyle risk factors and antihypertensive medication use. Hypertension was defined as a raised BP (a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg based on the mean of the second and third readings) or being on antihypertensive medication. Controlled BP was defined as being on medication with a BP <140/90 mmHg. Participants found to have raised BP were provided with diet and lifestyle advice and referred to a health facility of their choice for further management.

Data were collected locally via the MMM app and submitted to the central MMM team for cleaning and analysis. In cases where any BP reading was missing, to ensure comparability between participants, the average of the second and third readings was estimated by multiple imputation using chained equations, based on global data as described previously.⁵ For comparison with other countries participating in MMM, results are also presented after age and sex standardization using the WHO world standard population, and assuming an equal gender split.¹⁰ The study received ethical approval from Kenyatta National Hospital/University of Nairobi Research and Ethics Committee, reference number—P659/08/2021. Funding was received from MMM and Servier.

Results

In total, 9605 participants were screened during MMM22 in Kenya with the majority (66.8%) screened in outdoor public areas. The mean (SD) age was 43.0 (15.3) years and 4218 (43.9%) were female and 9154 (95.3%) of Black ethnicity. Of all participants, 3406 (35.5%) reported never having had a BP measured before. The majority had never or rarely consumed alcohol (8089; 84.2%) and were not currently smoking (8968; 93.4%). Only 4653 (48.4%) met the WHO physical activity guidelines.¹¹

Multiple imputation was used to estimate missing BP readings for 3042 (31.7%) participants missing data on the second or third BP reading. Of all participants, 3167 (33.0%) were found to have hypertension, of whom 982 (31.0%) were aware, and 936 (29.6%) were on antihypertensive medication (Table 1). Of those on antihypertensive medication, 346 (37.0%) had controlled BP, and of all hypertensives, 10.9% had controlled BP. In total, 2821 (29.4%) participants had uncontrolled or inadequately controlled BP.

Table 1.

Total participants and numbers with hypertension, awareness on medication and with controlled blood pressure, before and after age and sex standardization

	Total participants	Number (%) with hypertension	Number (%) of hypertensives aware	Number (%) of hypertensives on medication	Number (%) of those on medication with controlled BP	Number (%) of all hypertensives with controlled BP
Actual	9605	3167 (33.0)	982 (31.0)	936 (29.6)	346 (37.0)	346 (10.9)
Standardized	9605	3104 (32.3)	1015 (32.7)	966 (31.1)	389 (40.3)	389 (12.5)

After age and sex standardization, 3104 (32.3%) were found to have hypertension, of whom 1015 (32.7%) were aware, 966 (31.1%) were on antihypertensive medication and 389 (12.5%) were controlled (Table 1). Females and older individuals were more likely to be aware, to be on medication and to have controlled BP.

Of those on medication, the majority were on two (517, 55.2%) antihypertensive medication class, with 342 (35.5%) on one drug class only 721 (77.0%) reported taking their medication regularly and the majority (687, 73.4%) reported that they paid fully for their medication.

Compared with those with no formal education, having 1–6 years of education was associated with higher systolic and diastolic BP in linear regression models adjusted for age, sex, and antihypertensive medication use (Figure 1A). Meeting the WHO physical activity guidelines¹¹ (at least 150 min of moderate physical activity or 75 min of vigorous activity per week) was associated with lower SBP and higher diastolic BP, relative to those not meeting the activity guidelines. In female participants, a history of hypertension in a previous pregnancy was associated with higher SBP and DBP after adjustment for age and antihypertensive treatment (Figure 1B).

Figure 1.

(A and B) Determinants of blood pressure in the screened population. (A) Difference in mean blood pressure in participants with risk factors compared with those without from linear regression models adjusted for age, sex, and antihypertensive medication. (B) Difference in mean blood pressure in women with a history of hypertension in previous pregnacy, HRT use and contraception use compared with those women without these factors from linear regression models, adjusted for age and antihypertension medication.

Discussion

More than a third (35.5%) of participants had never had a previous BP measurement, pointing to an ongoing need for more awareness and screening programs such as MMM. The campaign identified a total of 2821 (29.4%) participants with untreated or inadequately treated BP, highlighting the scale of hypertension in Kenya. The proportion of those reported to be hypertensive (33.0%) is the highest ever reported during the MMM campaigns in Kenya. Considering the last nationally representative survey done in 2015 reported an age-standardized prevalence of 24.5%, and the 2021 MMM campaign a prevalence of 28.2%, this could indicate an upward trend and an increase in the disease burden.⁴

The hypertension awareness and control rates have increased from that reported in the national survey from 15.6% to 31% and from 3% to 10.9%, respectively; however, the control rates remain alarmingly low. This could be partly attributed to awareness campaigns such as MMM. The findings indicate lower awareness (31.0% in MMM22 compared with 45.9% in MMM21) and treatment rates (29.6% in MMM22 compared with 42.0% in MMM21) among those with hypertension; however, this could be attributed to the opportunistic nature of the campaign leading to heterogeneity in the population reached. The fact that majority of patients who were aware of their hypertension status were on medication emphasizes the importance of awareness creation in improving overall treatment and control rates.

A significant proportion of those on treatment were on one antihypertensive class (36.5%). And 55.2% were on two drug classes. This is comparable with current guidelines, which recommend dual antihypertensive therapy at first line treatment for the majority of hypertension patients.¹² A significant proportion (73.4%) reported that they pay fully for their medication. These findings warrant further evaluation as they could be contributing to the sub-optimal control rates among those on medication. Single pill combination therapy is now recommended to reduce pill burden and enhance adherence, and future MMM campaigns should assess their utilization.¹²

Strengths and limitations

A strength of the MMM campaign is the use of a standardized protocol across countries, which aids comparability of findings. Participants in MMM were recruited opportunistically using convenience sampling, and as a result, MMM hypertension prevalence estimates cannot necessarily be interpreted as estimates of national prevalence. Hypertension was defined based on three BP readings at a single visit for pragmatic reasons, which is not the optimal method of diagnosis at the individual level as recommended in guidelines. Consequently, the rate of hypertension detected is likely to represent an overestimate.¹²

Conclusion

Hypertension awareness and control rates have remained low over the years, which warrant critical evaluation of possible contributors, including low awareness rates and access to optimal treatment. The MMM campaign remains a much-needed initiative to help identify untreated and inadequately treated individuals, combat low awareness rates, and provide much-needed data to stimulate effective hypertension control programs at a national level in Kenya.

Funding

May Measurement Month 2022 was partially supported by Servier Laboratories. They however had no role in study design, data collection, data analysis, data interpretation, writing of the manuscript nor submission for publication. MMM supported the campaign with BP machines.

Data availability

Data are not publicly available but access can be requested with permission from the MMM Management Board, on request through the MMM website: maymeasure.org.