A Clinicopathological Study of 267 Patients with Diabetic Kidney Disease Based on the Renal Pathology Society – 2010 Classification System

INTRODUCTION: Renal biopsy is primarily indicated in patients with diabetes mellitus (DM) with proteinuria, to diagnose non-diabetic renal disease (NDRD). However, Renal Pathology Society classification (RPSc) – 2010 has classified diabetic nephropathy (DN) into four classes of glomerular lesions with a separate scoring for tubulointerstitial and vascular lesions. Paucity of data from Indian subcontinent prompted us to plan this study to classify DN on biopsy as per the RPSc and correlate the clinical profile with histology. MATERIALS AND METHODS: Patients with DM who underwent renal biopsy for various indications (between Aug 2013 and Nov 2015) were included in the study. DN on histology was classified according to RPSc. Histopathology lesions of DN were correlated with clinical and biochemical profiles. RESULTS: Of the 267 patients studied, 252 (94.3%) were type 2 DM. NDRD alone was seen in 65 (24.34%), DN in 161 (60.3%), and NDRD with DN in 41 (15.3%). The most common indications for biopsy were rapidly progressive renal failure (76.7%) and nephrotic syndrome (16.4%). The most common glomerular class was class IV (43.5%), followed class III (41%), class II (13.3%), and class I (1.9%). The most common NDRD seen was acute interstitial nephritis (AIN) in 20.2% and is frequently associated with class III. Tubulointerstitial chronicity and not the arteriolar chronicity, was correlated with low estimated glomerular filtration rate (eGFR). CONCLUSIONS: Most patients with DN subjected to renal biopsy were in class IV, and AIN was the most common NDRD. Only tubulointerstitial chronicity correlated with low eGFR.