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

Abstract

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, HbA 1c , 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. Diabet. Med. 25, 536–542 (2008) Keywords Chennai Urban Rural Epidemiology Study Eye Study, diabetic retinopathy, postprandial hyperglycaemia, risk factors, South Indians Abbreviations BP, blood pressure; CURES, Chennai Urban Rural Epidemiology Study; DME, diabetic macular oedema; DR, diabetic retinopathy; ETDRS, Early Treatment Diabetic Retinopathy Study; FPG, fasting plasma glucose; HbA 1c , glycated haemoglobin; IFG, impaired fasting glucose; KD, known diabetic subjects; LDL, low-density lipoprotein; NDD, newly detected diabetic subjects; NPDR, non-proliferative diabetic retinopathy; OGLA, oral glucose-lowering agent; PPPG, postprandial plasma glucose; PDR, proliferative diabetic retinopathy; WHR, waist–hip ratio