Regional and sex differences in the prevalence and awareness of hypertension across six sites in sub-Saharan Africa: an H3Africa AWI-Gen study

Abstract

Background

There is a high prevalence of hypertension and related cardiovascular diseases in sub-Saharan Africa yet few large studies exploring hypertension in Africa are available. The actual burden of disease is poorly understood and awareness and treatment to control it is often suboptimal.

Objectives

To report the prevalence of measured hypertension and to assess awareness and control of blood pressure among older adults in rural and urban settings in six sites located in west, east and southern Africa. In addition, we examined regional, sex, and age differences related to hypertension.

Methods

A population-based cross-sectional study was performed at six sites in four African countries - Burkina Faso (Nanoro), Ghana (Navrongo), Kenya (Nairobi) and South Africa (Agincourt, Dikgale, Soweto). Blood pressure measurements were taken using standardized procedures on 10,696 adults aged 40 to 60 years. Hypertension was defined as SBP ≥ 140mm Hg and/or DBP ≥ 90 mm Hg or taking anti-hypertensive medication.

Results

The mean prevalence of hypertension ranged from 15.1% in Nanoro to 54.1% in Soweto. All three of the South African sites had a mean prevalence of hypertension of over 40.0%, significantly higher than Nairobi (25.6%) and Navrongo (24.5%). Prevalence increased with age in both sexes and at all sites. A significantly higher prevalence of hypertension was observed in women in Agincourt, Dikgale and Nairobi, while in Nanoro this trend was reversed. Within the hypertensive group the average proportion of participants who were aware of their blood pressure status was only 39.4% for men and 53.8% for women, and varied widely across sites.

Conclusions

Our study demonstrates that the prevalence of hypertension and the level of disease awareness differ not only between but also within sub-Saharan African countries. Each nation must tailor their regional hypertension awareness and screening programs to match the characteristics of their local populations.