Risk factors for diabetic retinopathy in a South Indian Type 2 diabetic population—the Chennai Urban Rural Epidemiology Study (CURES) Eye Study 4

AIMS: To determine risk factors for diabetic retinopathy (DR) in an urban South Indian Type 2 diabetic population. METHODS: The Chennai Urban Rural Epidemiology Study is a large cross-sectional study conducted in Chennai, South India. A total of 1736 Type 2 diabetic subjects were recruited for this study, which included 1382 known diabetic subjects (90.4% response rate) and 354 randomly selected, newly detected diabetic subjects diagnosed by oral glucose tolerance test. All subjects underwent four-field stereo retinal colour photography, graded by the Early Treatment Diabetic Retinopathy Study protocol. RESULTS: Of the 1736 Type 2 diabetic subjects photographed, photographs could be graded in 1715 subjects. Stepwise ordinal logistic regression analysis revealed that male gender (P = 0.041), duration of diabetes (P < 0.0001), glycated haemoglobin (HbA(1c); P < 0.0001), macroalbuminuria (P = 0.0002) and insulin therapy (P = 0.0001) were significantly associated with severity of DR. The risk for developing DR was 7.7 times (95% confidence interval 4.71-12.48, P < 0.0001) for elevated postprandial plasma glucose levels compared with 4.2 times (95% confidence interval 2.78-6.34, P < 0.0001) for elevated fasting plasma glucose when the fourth quartile values were compared with the first quartile glucose values. CONCLUSIONS: In South Indian Type 2 diabetic subjects, duration of diabetes, HbA1c, male gender, macroalbuminuria and insulin therapy were independent risk factors for severity of DR. Postprandial hyperglycaemia indicated a higher risk for DR compared with elevated fasting plasma glucose levels.