Burden of non-communicable diseases in South Asia

Editor—India is widely believed to be on the verge of an epidemic of coronary heart disease, as expressed by Ghaffar et al in their clinical review.¹,² We believe this assumption to be based on weak evidence.

We found one meta-analysis, reporting a ninefold increase in urban India (1-9%) and twofold increase (2-4%) in rural India between the 1960s and 1990s.³ We believe these results to be inaccurate because of the poor quality of underlying data and because comparisons were based on studies defining coronary heart disease differently. Coronary heart disease was measured by using either Minnesota coded electrocardiograms or clinically defined using non-validated translations of the Rose angina questionnaire. The questionnaire tends to give greater positive results and is less valid in women and South Asian populations.⁴,⁵

Our review, which is currently undergoing peer review, focused on Minnesota coded electrocardiograms to provide an objective measure. We reviewed 31 studies published between 1974 and 2002.

The quality of the data was generally poor as many did not fulfil basic criteria for epidemiological research. Furthermore, research was generally concentrated on a small area around the capital, Delhi. We found the prevalence in urban India to be higher than rural areas in men and women. We found no clear rise in prevalence, including age specific rates, in men over a 27 year period, with some modest evidence of a rise in women.

A major expansion of research and surveillance is urgently needed, with new studies following more rigorous and standardised methods to permit comparison over time, between locations, and between and within populations. Only then will the true extent and impact of the disease in South Asia be known. In the meantime, claims of a massive epidemic need to be interpreted with caution.