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

Abstract

The May Measurement Month (MMM) campaign was carried out in Mozambique in 2022 with the aim of raising awareness of raised blood pressure (BP). Here, we report on the findings of the campaign. Adults aged ≥18 years were recruited opportunistically at Zambézia, Sofala, and Maputo city, in Northern, Central, and Southern regions of Mozambique, respectively. Three seated 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 and/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, 8276 were screened, with a mean age of 36.9 years and 61.6% of whom were female. Of all participants, 2486 (30.0%) had hypertension, of whom 1122 (45.1%) were aware, and 735 (29.6%) were on antihypertensive medication. Of those on antihypertensive medication, 285 (38.8%) had controlled BP, and of all participants with hypertension, 11.5% had controlled BP. In conclusion, the MMM campaign in Mozambique identified significant numbers of participants with either untreated or inadequately treated hypertension, calling attention to the need to improve the overall hypertension care cascade. There is an urgent need to increase awareness, improve access to appropriate antihypertensive medication and better follow up those on treatment.

Introduction

Raised blood pressure (BP) is one of the largest contributors to the global burden of disease.¹ Mozambique is a vast (786 380 km²) and populous (28 861 863 people) low income country located in south east coast of Africa.² Two nationally representative surveys with a 10-year interval (2005 and 2014/2015) were conducted in the country, revealing a significant increase on the prevalence of hypertension in adults, from 33.1% to 38.9%. On the other hand, there were no improvements in the prevalence of awareness, treatment, and control, which remained very low.^3,4 As a consequence, complications of uncontrolled high BP, particularly heart failure and stroke, are frequently seen in patients admitted to hospitals. In fact, a case registry conducted among all Maputo’s secondary and tertiary referral health units in 2005/2006, already portrayed an alarming annual incidence rate of stroke (260.1 per 100 000 people, adjusted to the world reference population) and a case fatality rate of 33.3%, in-hospital, and 39.6% at 28 days.⁵

May Measurement Month (MMM) was initiated in 2017 by the International Society of Hypertension (ISH) and has since run annually, except for 2020 due to the COVID-19 pandemic. In 2022, the MMM campaign continued, with an aim of continuing to raise awareness of the dangers of raised BP and included 757 350 participants worldwide.⁶ Mozambique participated in all MMM campaigns since 2017. In MMM17, among 4454 screened participants, 1371 (31.1%) had hypertension and only 272 (6.1%) were on antihypertensive medications. Among individuals not taking antihypertensive medicines, 1099 (26.6%) were hypertensive and among those receiving antihypertensive medication, 166 (61.6%) had uncontrolled BP.⁷

In this paper, we report on the findings of the MMM22 campaign in Mozambique.

Methods

May Measurement Month is a cross-sectional opportunistic survey of consenting adults aged 18 years or over. The programme in Mozambique was co-ordinated by Mozambican Heart Association (AMOCOR) with support from Doctors with Africa (CUAMM), over the month of July. Screening sites were set up mainly at participant’s homes in peri-urban neighbourhoods and in public areas such as markets, in Beira, Quelimane, and Maputo city. After selection of 20 volunteers in each site, a researcher conducted a one-day training in each site. The campaign was advertised via community leaders and local health authorities. In accordance with the standard MMM protocol, and after signing informed consent, participants ideally had three seated BP readings measured at 1 min intervals.⁶ Omron automated devices were used to measure BP. A questionnaire was 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 and/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. All participants received written information regarding their measured BP and diet and lifestyle advice. Participants found to have raised BP were recommended to attend the local primary health facility.

Data were collected locally on paper forms and transferred on the same day to an excel spreadsheet 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.⁶ For comparison with other countries participating in MMM, results are also presented after age and sex standardization using the World Health Organization (WHO) world standard population, and assuming an equal gender split.⁸ The study was authorized by the Ministry of Health, received administrative authorization at provincial level, and was approved by the National Bioethics Committee for Health.

Results

In total, 8276 participants were screened during MMM22 in Mozambique. The mean (standard deviation) age was 36.9 (16.0) years, and 5097 (61.6%) were female. A total of 99.8% of participants were of Black ethnicity. Of all participants, 2362 (28.5%) reported never having had a BP measured before. Multiple imputation was used to estimate missing BP readings for 39 (0.5%) participants missing data on the second and/or third BP reading. Of all participants, 30.0% were found to have hypertension, of whom 45.1% were aware, and 29.6% were on antihypertensive medication (Table 1). Blood pressure was controlled in 38.8% of those on antihypertensive medication and 11.5% of all hypertensives. Of participants not on antihypertensive medication, 1751 (23.2%) had raised BP. In total, 2201 (26.6%) were found to have either untreated or inadequately treated hypertension.

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	8276	2486 (30.0)	1122 (45.1)	735 (29.6)	285 (38.8)	285 (11.5)
Standardized	8268a	3157 (38.2)	1351 (42.8)	965 (30.6)	473 (49.0)	473 (15.0)

^aStandardized total lower than actual total, as eight participants did not have information recorded on age or sex.

After age and sex standardization, 3157 (38.2%) were found to have hypertension, of whom 1351 (42.8%) were aware, 965 (30.6%) were on antihypertensive medication, and 473 (15.0%) were controlled (Table 1).

In general, the prevalence of hypertension and hypertension awareness and treatment increased with age, while control among those on medication decreased with age. A higher proportion of female hypertensive participants were aware (52.6% vs. 32.9% for male), on medication (34.9% vs. 20.3% for male), and controlled (39.1% of those on medication vs. 37.7% for male). There were significant differences in BP values according to education level, with a lower systolic and diastolic BP⁵ when the level of education was at least 7 years. Diastolic BP was significantly lower when the WHO guideline target for physical activity was met, but no significant differences were observed with smoking status or alcohol intake levels (Figure 1).

Figure 1.

Differences in mean diastolic and systolic BP according to risk factors, when compared to those without the risk factor. ^┼Compared to no years of education. *Compared to ‘never/rarely’ as baseline. ^150min of moderate exercise or 75 min of more vigorous exercise per week.

Discussion

The MMM22 programme identified 2486 screenees with hypertension, among the 8276 screened. Among participants with hypertension, fewer than half were aware and only 29.6% were on medication.

Furthermore, a total of 2201 (26.6%) participants had untreated or inadequately treated hypertension, highlighting the scale of hypertension in Mozambique. MMM22 found a lower percentage of hypertension compared to the prevalence found in the last national survey conducted in 2014/15 (38.9%), which might be explained by the difference in population included, particularly the lower age of participants (from 18 years) included in MMM22. In addition, the percentages of awareness, treatment, and control found in MMM22 were higher, which may in part reflect the fact that MMM22 did not include rural inhabitants, previously shown to present lower prevalence of awareness.⁴ In accordance to the national survey,⁴ women had better awareness, treatment, and control of hypertension than men. Even so, 60.9% of females on antihypertension medication had uncontrolled BP, reflecting the need to improve education and access to care. In fact, low access to cardiovascular medication overall has been shown in the country.⁹

Previous estimates from MMM17 found a similar prevalence of high BP (31.1%) and the same high prevalence of uncontrolled BP (61.6%) among those receiving antihypertensive medication,⁷ depicting the need to improve preventive measures and increase access to adequate care.

Strengths and limitations

A strength of the MMM campaign is the use of a standardized protocol across countries, which aids comparability of findings. Participants were recruited opportunistically using convenience sampling, only including three provinces and not including rural areas. As such, estimates should not be interpreted as 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.¹⁰ Consequently, the rate of hypertension detected is likely to represent an overestimate.

Conclusion

The MMM22 campaign identified significant numbers of participants with either untreated or inadequately treated hypertension in Mozambique, calling attention to the need to improve the overall hypertension care cascade. There is an urgent need to increase access to appropriate antihypertensive medication, improve education, particularly for women, and follow up patients on treatment, with special attention to older people.

Funding

The study was funded by AMOCO, MMM, and CUAMM.

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.