Clinicopathological study of nondiabetic renal disease in type 2 diabetic patients: A single center experience from India

Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM), leading to chronic kidney disease/end-stage renal disease. Wide spectrum of nondiabetic renal diseases (NDRD) is reported in type-2 diabetes (type-2 DM). We carried out this single-center study to find clinical, laboratory, and histological features of NDRD in type-2 DM patients and to assess the prevalence of NDRD in India. A single-center retrospective study which included analysis of renal biopsies from patients with type-2 DM, performed between January 2008 and September 2016. Biopsy findings were categorized into three groups, Group-I (isolated NDRD); Group-II (NDRD superimposed on underlying DN); and Group-III (isolated DN). Out of 152 diabetic patients (111 males and 41 females), 35 (23.03%) patients were of Group-I (isolated NDRD), 35 (23.03%) of Group-II (NDRD superimposed on underlying DN), and 82 (53.95%) of Group-III (isolated DN). The mean age (in years) was 55.08 ± 10.71, 55.65 ± 8.71, and 54.45 ± 9.01 respectively in Group-I, II, and III. Nephrotic syndrome (NS) was the most common clinical presentation in all groups. Duration of DM was significantly shorter in Group-I than in Group-II. Diabetic retinopathy was absent in Group-I. Proteinuria was more in Group-III than Group-I. Low serum C3 and/or C4 levels was observed in five (14.29%) cases of Group-I and Group-II each and two (2.43%) cases of Group-III. Nearly, 70 (46.05%) patients were found to have NDRD either in isolated form or as combined lesions. The most common histological types of NDRD were acute tubulointerstitial nephritis (38.57%) followed by benign nephrosclerosis (15.72%), membranous nephropathy (10%), IgA nephropathy (7.14%), and membranoproliferative glomerulonephritis (7.14%). The incidence of NDRD (with/without DN) in type-2 DM is very high. Shorter duration of diabetes, hematuria, absence of retinopathy, low serum complement levels, and nephrotic range proteinuria are predictors of NDRD.