Prevalence of diabetic retinopathy in India: Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetics Study report 2.

OBJECTIVE The aim of the study was to estimate the prevalence of diabetic retinopathy in an urban Indian population older than 40 years. DESIGN A population-based cross-sectional study. PARTICIPANTS Five thousand nine hundred ninety-nine subjects residing in Chennai, India, were enumerated. METHODS A multistage random sampling, based on socioeconomic criteria, was followed. Identified subjects with diabetes mellitus (based on the World Health Organization criteria) underwent detailed examination at the base hospital. The fundi of all patients were photographed using 45 degrees , 4-field stereoscopic digital photography. The diagnosis of diabetic retinopathy was based on Klein's classification of the Early Treatment Diabetic Retinopathy Study scale. MAIN OUTCOME MEASURES These included age- and gender-adjusted prevalence of diabetes and diabetic retinopathy, and correlation of prevalence with history-based risk factors. RESULTS The age- and gender-adjusted prevalence rate of diabetes in an urban Chennai population was 28.2% (95% confidence interval [CI], 27.0-29.3), and the prevalence of diabetic retinopathy in general population was 3.5% (95% CI, 3.49-3.54). The prevalence of diabetic retinopathy in the population with diabetes mellitus was 18.0% (95% CI, 16.0-20.1). History-based variables that were significantly associated with increased risk of diabetic retinopathy included gender (men at greater risk; odds ratio [OR], 1.41; 95% CI, 1.04-1.91); use of insulin (OR, 3.52; 95% CI, 2.05-6.02); longer duration of diabetes (>15 years; OR, 6.43; 95% CI, 3.18-12.90); and subjects with known diabetes mellitus (OR, 2.98; 95% CI, 1.72-5.17). Differences in the socioeconomic status did not influence the occurrence of diabetic retinopathy. CONCLUSIONS The prevalence of diabetic retinopathy was 18% in an urban population with diabetes mellitus in India. The duration of diabetes is the strongest predictor for diabetic retinopathy. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.