Many types of heart disease as well as some of its associated risk factors, which are traditionally only associated with high-income countries, are increasing in incidence in African people. This is worsening the threat to these populations and only deepening the challenges governments and doctors must face in these areas. These conclusions were published in an article in The Lancet released on March 14, 2008.

The epidemic of cardiovascular disease (CVD) in developed countries has been well documented, from its causes to its consequences. In low-income and middle-income countries, where malnourishment and infectious disease are also common, there are few data to describe CVD’s effects.

To explore this, the Heart of Soweto Study was performed by Professor Simon Stewart, Cardiovascular Research Unit, Chris Hani Baragwanath Hospital, University of the Witwatersrand, Johannesburg, South Africa, and Baker Heart Research Institute, Melbourne, Australia, and colleagues. The study focused on the clinical range of disorders related to CVD in patients presenting for the first time to a cardiology unit in Chris Hani Baragwanath Hospital in one year. Data was recorded for 4,162 patients with confirmed CVD, 1,593 of whom were newly diagnosed and 2,569 of whom were previously diagnosed and under treatment. Additionally, they established a registry for newly diagnosed patients with relevant data.

Upon examination it was found that, of the newly diagnosed study population, 85% (1,359) were black Africans and 59% (939) were women. In the same population, women had an average age of 53 years, while men were older with a mean of 55 years. Approximately 25% of the patients were younger than 40 years old.

The most common primary diagnosis was heart failure, and this was present in 44% of the patients. Compared to the rest of the population, black Africans were 46% more likely to be diagnosed with heart failure, but only 10% as likely to be diagnosed with coronary artery disease. In general, the presence of CVD risk factors was very high: 56% of the patients had hypertension or high blood pressure; 44% of the patients with hypertension were obese. 59% (933) newly diagnosed patients showed several risk factors, while only 8% (209) of this population showed no identifiable risk factors.

This study, according to the authors, will have important implications on actions taken to prevent and treat heart disease, not just in Soweto, but also for other urban communities in Africa that are presently experiencing similar epidemiological changes in their disease profiles. Presently, a broad range of advanced conditions are included in the spectrum of Soweto’s heart disease. This includes the infectious diseases usually expected in African populations, such as rheumatic valvular diseases, cardiomyopathies, tuberculosis linked pericardial effusion and diseases exacerbated by HIV incidence. However, also included are newer non-communicable diseases that are associated with advanced clinical presentation, which usually are reported in high-income countries, such as hypertensive heart disease and coronary artery disease.

The authors point out in particular their concern that the patients most likely to be obese in both this hospital and in the general community were black African women, and that this group represents a greater proportion of the whole than black African men. “[This] is especially noteworthy in view of the typical male dominance seen in cohorts from developed countries.”They conclude, highlighting the final implications of their new data: “The combination of common preventable risk factors and late clinical presentations – especially heart failure – represents a particular challenge to improve primary and secondary prevention strategies to not only reduce the number of new cases of cardiovascular disease but also improve health outcomes for those with pre-established disease.”

Dr Harvey White, Auckland City Hospital, New Zealand, and Dr Anthony Dalby, Milpark Hospital, Johannesburg, South Africa, contributed an accompanying Comment in which they point out the importance of this study along with some challenges. They say: “The major challenge is how to increase health resources. A recurring theme in Africa is the lack of reliable statistics. This registry, from one of the largest urban populations of black Africans, goes a long way to correcting that deficit in Soweto.”

Spectrum of heart disease and risk factors in a black urban population in South Africa (the Heart of Soweto Study): a cohort study
Karen Sliwa, David Wilkinson, Craig Hansen, Lucas Ntyintyane, Kemi Tibazarwa, Anthony Becker, Simon Stewart
The Lancet – Vol. 371, Issue 9616, 15 March 2008, Pages 915-922
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Heart disease in Soweto: facing a triple threat
Harvey D White, Anthony J Dalby
The Lancet – Vol. 371, Issue 9616, 15 March 2008, Pages 876-877
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Written by Anna Sophia McKenney