Prevalence and Risk Factors of Diabetic Nephropathy in an Urban South Indian Population: The Chennai Urban Rural Epidemiology Study (CURES 45)

Abstract

OBJECTIVE— The aim of this study was to determine the prevalence of diabetic nephropathy among urban Asian-Indian type 2 diabetic subjects. RESEARCH DESIGN AND METHODS— Type 2 diabetic subjects (n 1,716), inclusive of known diabetic subjects (KD subjects) (1,363 of 1,529; response rate 89.1%) and randomly selected newly diagnosed diabetic subjects (NDD subjects) (n 353) were selected from the Chennai Urban Rural Epidemiology Study (CURES). Microalbuminuria was estimated by immunoturbidometric assay and diagnosed if albumin excretion was between 30 and 299 g/mg of creatinine, and overt nephropathy was diagnosed if albumin excretion was 300 g/mg of creatinine in the presence of diabetic retinopathy, which was assessed by stereoscopic retinal color photography. RESULTS— The prevalence of overt nephropathy was 2.2% (95% CI 1.51–2.91). Microalbuminuria was present in 26.9% (24.8 –28.9). Compared with the NDD subjects, KD subjects had greater prevalence rates of both microalbuminuria with retinopathy and overt nephropathy (8.4 vs. 1.4%, P 0.001; and 2.6 vs. 0.8%, P 0.043, respectively). Logistic regression analysis showed that A1C (odds ratio 1.325 [95% CI 1.256 –1.399], P 0.001), smoking (odds ratio 1.464, P0.011), duration of diabetes (1.023, P0.046), systolic blood pressure (1.020, P 0.001), and diastolic blood pressure (1.016, P0.022) were associated with microalbuminuria. A1C (1.483, P 0.0001), duration of diabetes (1.073, P 0.003), and systolic blood pressure (1.031, P 0.004) were associated with overt nephropathy. CONCLUSIONS— The results of the study suggest that in urban Asian Indians, the prevalence of overt nephropathy and microalbuminuria was 2.2 and 26.9%, respectively. Duration of diabetes, A1C, and systolic blood pressure were the common risk factors for overt nephropathy and microalbuminuria.