Nondiabetic renal disease in patients with type 2 diabetes

Diabetic nephropathy (DN) is one of the major complications of type 2 diabetes mellitus (T2DM). The diagnosis of DN is mostly clinical. Kidney biopsy is indicated only if nondiabetic renal disease (NDRD) is suspected. This study is aimed to assess the prevalence of NDRD and to determine predictor and prognostic factors of DN, NDRD. It was a retrospective analytic study including T2DM patients in whom renal biopsies were performed at our department from 1988 to 2014. Seventy-five patients were included. Mean age was 52.7 years with sex ratio at 1.56. Renal biopsy findings were isolated NDRD in 33 cases, NDRD superimposed on DN in 24 cases, and isolated DN in 18 cases. Most common NDRD found were focal segmental glomerulosclerosis (21%) and membranous nephropathy (19%). Multivariate analysis showed that the absence of ischemic heart disease [odds ratio (OR) = 0.178, 95% confidence interval (CI) = 0.041-0.762], absence of peripheral vascular disease (OR = 0.173, 95% CI = 0.045-0.669), and presence of hematuria (OR = 7.200, 95%CI = 0.886-58.531) were independent predictors of NDRD. 24 patients reached end-stage renal disease 55% in DN group, 16% in DN associated to NDRD group, and 30% in NDRD group. The prevalence of NDRD found in our study confirmed usefulness of renal biopsy in patients with T2DM, especially in those without degenerative complications, hypertension, and insulin therapy.