Prevalence and risk factors of diabetic nephropathy in an urban South Indian population: the Chennai Urban Rural Epidemiology Study (CURES 45).

Objective: The aim of this study was to determine the prevalence of diabetic nephropathy among urban Asian-Indian type 2 diabetic subjects.

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 microg/mg of creatinine, and overt nephropathy was diagnosed if albumin excretion was > or = 300 microg/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, P = 0.011), duration of diabetes (1.023, P = 0.046), systolic blood pressure (1.020, P < 0.001), and diastolic blood pressure (1.016, P = 0.022) 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.