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SA has highest blood pressure in southern Africa

- Wits University

A study by Wits scientists and peers has revealed that South Africa has the highest prevalence of hypertension in southern Africa.

South Africa also has the largest number of people whose blood pressure is still not controlled, even whilst on treatment.

These were among the findings of a paper, entitled: Stark Regional and Sex Differences in the Prevalence and Awareness of Hypertension: An H3Africa AWI-Gen Study Across 6 Sites in Sub-Saharan Africa published in Global Heart today.

Hypertension is abnormally high blood pressure. It is a condition in which the force of the blood against the artery walls is too high. This causes the heart to work harder than normal, which is dangerous.

Professor Michèle Ramsay of the Sydney Brenner Institute for Molecular Bioscience at Wits and Dr Osman Sankoh from the International Network for the Demographic Evaluation of Populations and Their Health (INDEPTH) published the ground-breaking study, which reports on the prevalence of hypertension in approximately 10,000 older people at six sites across sub-Saharan Africa. The study also assessed awareness and control of blood pressure.

Dr Stuart A. Ali, Project Manager and Researcher at the Institute, says: “This knowledge provides a platform from which we can explore the environmental and genetic contributions to cardiovascular disease in Africa.”

This was a first-of-its-kind cross-sectional study and it revealed astounding results – there were stark differences in the prevalence, awareness, and control of high blood pressure in the cohort studied. Prevalence of hypertension ranges from:

  • 15% in the west of southern Africa
  • 25% in the east of southern Africa
  • between 42% and 54% in South Africa

Pooled analysis also showed some gender differences. For men, only 40% were aware of their hypertension condition. Of those who knew and were being treated, only 39% had controlled blood pressure. For women, the picture was better with 54% being aware of their hypertension condition, and of those undergoing treatment, 51% had controlled blood pressure.

South Africa has the highest prevalence of hypertension and also the largest number of people whose blood pressure is still not controlled, even whilst being on treatment

Cardiovascular diseases, particularly hypertension, are considered diseases of the aging population. Increased life expectancy from access to antiretroviral treatment to those with HIV is expected to increase the incidence of hypertension. Consequently, non-communicable diseases, including hypertension, need to be prioritized and managed to reduce the public health burden and avert a new epidemic in Africa.

This research supports the need for regionally tailored interventions. For example, whilst the east of Africa shows lower levels of hypertension, possibly due to being in the early phases of an epidemiological and health transition, levels of awareness and control are also low.

“Further detailed research is necessary if we are to stop the ticking time bomb of hypertension and other cardiovascular diseases,” says Ali.

More research is needed to establish systems in health facilities that will increase the proportion of patients with controlled blood pressure.  Improved treatment quality and increased adherence to anti-hypertensive treatment will facilitate management of this potential epidemic.

The study was conducted under the auspices of the Wits-INDEPTH Partnership for Genomic studies (AWI-Gen) and leveraged the INDEPTH network’s existing Health and Demographic Surveillance System (HDSS) centres in rural Navrongo (Ghana), Nanoro (Burkina Faso), Agincourt and Dikgale (South Africa), urban Nairobi (Kenya), as well as the Developmental Pathways for Health Research Unit in urban Soweto. AWI-Gen is part of the Human Heredity and Health in Africa (H3Arica) Consortium.

The Wits-INDEPTH Partnership, through AWI-Gen, will continue to investigate the main drivers – and consequences – of hypertension in the different regions by revisiting study participants five years after their enrollment in the original study.