Prevalence of Nondiabetic Renal Disease in Patients with Type 2 Diabetes Mellitus with Clinicopathological Correlation: A Study from a Tertiary Care Center of Assam, India.

Diabetes mellitus is the most common cause of chronic kidney disease worldwide. The prevalence of nondiabetic renal disease (NDRD) among patients with type 2 diabetes mellitus (T2DM) varies widely. This study aimed to evaluate the renal biopsies performed on type 2 diabetic patients for suspicion of NDRD and to correlate clinicopathological findings. All T2DM patients aged > 18 years were included in this study, who had renal biopsy performed for the following reasons: recent-onset nephrotic syndrome, unexplained rapid deterioration of renal function, proteinuria not accompanied by retinopathy, and unexplained hematuria. Renal biopsy was analyzed by light microscopy and immunofluorescence. Based on biopsy findings, the patients were grouped into three: (i) isolated NDRD, (ii) NDRD ± diabetic nephropathy (DN), and (iii) isolated DN. A total of 140 patients were enrolled in this study. Recent-onset nephrotic syndrome was the most common indication for biopsy, followed by the presence of active urine sediment. Forty-two percent of the patients had isolated DN, while NDRD was seen in 34% and DN ± NDRD in 24%. Focal segmental glomerulosclerosis (FSGS) and IgA nephropathy were the most common causes of isolated NDRD, while chronic tubulointerstitial nephritis (CTIN) was common in NDRD plus DN. Short duration of diabetes, absence of diabetic retinopathy, and lower glycated hemoglobin were predictive of NDRD. NDRD was seen in 58% of the patients with atypical presentations. FSGS and CTIN were common in NDRD diseases. Judicious use of biopsy in diabetic patients with atypical presentation may help in the diagnosis of NDRD.