Prevalence of rheumatic heart disease in 4720 asymptomatic scholars from South Africa and Ethiopia

Background In Africa, screening for asymptomatic rheumatic heart disease (RHD) has been conducted in single communities using non-standardised echocardiographic criteria. The use of different diagnostic criteria has led to widely variable estimates of the prevalence of RHD in the same communities. Methods Randomly selected school pupils, from 4 to 24 years of age in Bonteheuwel and Langa communities of Cape Town, South Africa, and Jimma, Ethiopia, respectively, were screened for RHD according to standardised evidence-based echocardiographic diagnostic criteria of the World Heart Federation (WHF). Results We screened 4720 scholars. In South Africa (n=2720), 1604 (58.9%) were female and the mean age was 12.2 +/- 4.2 years. In Ethiopia (n=2000), 1012 (50.6%) were female and the mean age was 10.7 +/- 2.5 years. Echocardiographic screening revealed 55 cases of definite and borderline RHD by WHF criteria in South Africa and 61 cases in Ethiopia, corresponding to a prevalence of 20.2 cases per 1000 (95% CI 15.3 to 26.2) and 31 cases per 1000 (95% CI 23.4 to 39.0), respectively. The odds of detecting a scholar with RHD in Ethiopia were 1.5 times higher than in South Africa (OR 1.5; 95% CI 1.04 to 2.2, p=0.02). The prevalence of RHD was 27 cases per 1000 (95% CI 19.3 to 36.8) in Langa, and 12.5 cases per 1000 (95% CI 7.1 to 20.2) in Bonteheuwel. The odds of detecting a schoolchild with RHD in Langa compared with Bonteheuwel were 2.2 (OR 2.2; 95% CI 1.2 to 4.2, p=0.0071). Interpretation There were significant differences in detecting asymptomatic RHD in school pupils of different countries and in different communities within a country in sub-Saharan Africa. The variation in the prevalence of RHD between countries and communities has important implications for the modelling of the global burden of RHD.