Systematic review of rheumatic heart disease prevalence in children in developing countries: the role of environmental factors.

OBJECTIVES: To consider the worldwide prevalence of rheumatic heart disease in children in developing countries using surveys with uniform methodologies, and to consider the effect of environmental factors including socio-economic status, overcrowding, urbanization, nutrition and access to medical services on the distribution of rheumatic heart disease in developing countries.
METHODS: Sixty-one surveys of the prevalence of rheumatic heart disease in developing countries were found using a systematic review of MEDLINE from January 1976 to July 1999. Twenty-four studies were selected for comparison based on their uniform methodological and diagnostic techniques.
RESULTS: There is a high prevalence of rheumatic heart disease in the Pacific region with a lower prevalence in the Indian subcontinent, Asian, sub-Saharan African, Mediterranean, Latin American and Caribbean regions. However, aside from the Indian subcontinent, these regions have not been well studied, and it may be that the true prevalence is actually higher.
CONCLUSIONS: There is a lack of good quality prevalence surveys of rheumatic heart disease in developing countries. It appears that a threshold level where higher socio-economic status is associated with reduced prevalence of rheumatic heart disease is not reached in developing countries. Therefore, differences in prevalence between socio-economic groups in the one area cannot be detected. A similar case can be made for overcrowding. Many regions need well-designed studies of rheumatic heart disease that incorporate assessment of environmental factors as well as the study of the microbiological epidemiology of rheumatic heart disease and group A streptococci.