The Prevalence and Clinicopathological Spectrum of Nondiabetic Renal Disease in Patients with Diabetes in a Tertiary Care Center.

Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM), leading to end-stage renal disease. A wide spectrum of nondiabetic renal diseases (NDRDs) is reported in type 2 DM. We retrospectively reviewed the medical records of patients with type 2 DM who underwent a kidney biopsy from September 2019 to November 2021 at our center. Patients were grouped as having isolated DN, isolated NDRD, or mixed NDRD with underlying DN. According to the 379 renal biopsies performed during the study period, 57 patients had DM. The prevalence of DN, isolated NDRD, and combined pathologies was 36.8%, 35.1%, and 28.1%, respectively. The most common NDRD was infection-related glomerulonephritis (IRGN) (50.0%), followed by membranous nephropathy (3.0%), focal segmental glomerulosclerosis (10%), pyelonephritis (10%), minimal change disease (1.8%), fibrillary glomerulonephritis (1.8%), and ANCA-associated vasculitis (1.8%). The most common pathological finding of NDRD in the mixed group was IRGN (56.3%), followed by acute tubular injury (31.3%). The duration of DM was significantly shorter (4.8 ± 2.3 years vs. 9.7 ± 3.3 years, P = 0.035) in NDRD patients compared with patients with DN. NDRD was observed in 15% and mixed lesions in 25% of patients, with concomitant diabetic retinopathy (P = 0.029). We conclude that with increasing evidence of NDRD even in patients with DN, careful application of renal biopsies in diabetic patients would assist in the early diagnosis and institution of specific therapy for NDRD to ensure better patient and renal survival.