Risk factors for microvascular complications of diabetes among South Indian subjects with type 2 diabetes--the Chennai Urban Rural Epidemiology Study (CURES) Eye Study-5.

BACKGROUND

This study assessed the relationship between and risk factors for microvascular complications of diabetes in an urban South Indian type 2 diabetes population.

METHODS

Subjects with diabetes (n = 1,736) were selected from the population-based Chennai Urban Rural Epidemiology Study (CURES) Eye Study conducted on a representative population of Chennai city in south India. Four-field stereo retinal color photography was done, and diabetic retinopathy (DR) was classified according to the Early Treatment DR Study grading system. Neuropathy was diagnosed if the vibratory perception threshold of the big toe using biothesiometry was ≥ 20V. Overt nephropathy was diagnosed if the subjects had persistent macroalbuminuria (urinary albumin excretion ≥ 300 μg/mg of creatinine) and microalbuminuria if it was between 30 and 299 μg/mg of creatinine. Among the 1,715 subjects with gradable fundus photographs, 1,608 individuals who had information on all test parameters were included.

RESULTS

Overall, DR was present in 282 (17.5%), neuropathy in 414 (25.7%), overt nephropathy in 82 (5.1%), and microalbuminuria in 426 (26.5%) subjects. Eighteen subjects had all three microvascular complications of diabetes. The risk of nephropathy (odds ratio [OR] = 5.3, P<0.0001) and neuropathy (OR = 2.9, P<0.0001) was significantly higher among the subjects with sight-threatening DR compared to those without DR. Common risk factors identified for all the three microvascular complications of diabetes were age, glycated hemoglobin, duration of diabetes, and serum triglycerides. DR was associated with nephropathy after adjusting for age, gender, hemoglobin A1c, systolic blood pressure, serum triglycerides, and duration of diabetes (OR = 2.140, 95% confidence interval = 1.261-3.632, P = 0.005).

CONCLUSIONS

This is the first population-based study from India to report on all microvascular complications of diabetes and reveals that the association between DR and nephropathy is stronger than that with neuropathy.