The burden of heart failure in Africa

Abstract

Over the last few years, the focus of the international health community has shifted from communicable diseases as the main cause of morbidity and mortality in Africa (and indeed in the world in general) to non-communicable diseases. Relatively scant recent research suggests that in Africa cardiovascular (CV) diseases are a leading cause of morbidity and mortality, where up to 25% of admissions to hospitals are for CV disease, including hypertension (HTN). 14 Heart failure (HF) is the most common CV disorder and the main driver of CV adverse morbidity and mortality. 15 In this respect, the study by Ojji et al. in this month’s issue of the journal is a welcomed addition. In this hospital-based study, the authors report on the current spectrum of (CV) diseases in Abuja—the new and modern capital of the Federal Republic of Nigeria. The data from Abuja were compared with the findings in Soweto, a predominantly Black community in South Africa. The findings suggest that CV diseases in Abuja, Nigeria are mainly nonischaemic in origin and occur mainly in a younger and productive age group. Hypertension was found to be the most common cause, followed by dilated cardiomyopathies and rheumatic heart disease. The authors noted some subtle differences in the heart disease pattern in Abuja and Soweto. While there are higher rates of HTN and hypertensive HF in Abuja, ischaemic heart disease and right HF were more common in the Soweto study. As noted by the authors, this may be related to a higher burden of CAD and lung disease risk factors such as cigarette smoking, obesity, dyslipidaemia, and diabetes in Soweto compared with Abuja. Furthermore, peripartum cardiomyopathy is not as common a cause of CV disease and HF as expected. Given this relative lack of published data, putting the results of Ojji et al. into perspective is difficult. However, previous studies have found similar trends in different African countries and communities. 15 In most studies, HTN is followed by other disease entities that are less common outside of Africa, such as idiopathic dilated cardiomyopathy and rheumatic heart diseases. The Heart of Soweto registry from the Soweto township in South Africa, which is also described in the manuscript itself, found similar, although not identical trends (see above). In a registryof 2908 patients presenting for CV diseases to a clinic in Mzuzu central hospital in Malawi during a 5-year period, the most common causes of CV morbidity were rheumatic (34%), HTN (24%), cardiomyopathies (most commonly idiopathic dilated; 19%), and pericardial disease (14%). Atherosclerosis represented only 1–4% of cases. These trends are observed everywhere in Africa—in published and unpublished data, such as those depicted in a poster in the waiting area of a county hospital in Tzaneen; the Northern Province of South Africa (Figure 1). Indeed, similar results were published in studies from Nigeria 7 summarized in detail in the review by Ogah et al. These studies show that the prevalence of HTN in the general Nigerian population ranges from 8% to 46.4%. More importantly, it seems that the prevalence of HTN is increasing—from 8.6% reported in the only population-based study during the period from 1970 to 1979 to 22.55% during the period 2000–2011. HTN-related complications such as stroke, hypertensive heart disease (including hypertensive HF), andchronic kidneydisease is common andoften severe inhypertensive Nigerians. Late presentation is also common. Awareness, treatment, and control of HTN are low, as in many developing countries of the world. Regarding admissions for HF, in a smaller study from the Yaounde general hospital in Cameroon, the main causes of HF admissions were HTN (54%), cardiomyopathies (26%), and valvular heart diseases (24%). Ischaemic heart diseasewas the fifth most common aetiology (2.4%). In a registry of 1000 patients admitted for HF and followed prospectively by Damasceno et al., the most common causes of HF were HTN (45%) and rheumatic heart disease (14%), while ischaemic heart disease (8%) was not a common cause for HF. The study by Ojji et al., besides being one of the largest registries of CV diseases and HF in Africa, emphasizes two additional important aspects of CV diseases and HF and their treatment. First, the age of the patients affected is younger than in other world regions. Damasceno et al., Stewart et al., and Sliwa et al. have shown that CV diseases and HF occur in Africa at a younger age than outside Africa. In the series from Malawi, Soliman et al. found that the average age of patients presenting with CV diseases is as low as 40 years. Other studies describing CV admissions in Nigeria found the age of admission to be 50–55 years. 7,10 In the study of Ojji et al. the