Non-Diabetic Renal Disease in Patients with Type 2 Diabetes Mellitus–Experience from A Tertiary Care Hospital

Introduction: Diabetic nephropathy (DN) is a devastating complication of diabetes mellitus (DM) and leading cause of end stage renal disease (ESRD) globally. Spectrum of nondiabetic renal disease (NDRD) in Type-2 diabetes mellitus (T2DM) varies widely with evolving epidemiology and treatment strategies. Aim: To study the clinical features, laboratory findings, and histological features in the cases of NDRD diagnosed by renal biopsy in patients with type 2 DM. Material and Methods: We conducted a single centre retrospective study including patients with diabetes mellitus type 2 with clinically suspected NDRD who underwent renal biopsy from January 2018 to June 2023. Biopsy findings were categorized into three groups, Group-I (isolated NDRD); Group-II (NDRD superimposed on underlying DN); and Group-III (isolated DN). Results: Out of 96 diabetic patients (65 cases- 67.7% males and 31 cases- 32.3% females), 43 (44.79%) patients were of Group-I (isolated NDRD), 27 (28.13%) of Group-II (NDRD superimposed on underlying DN), and 26 (27.08%) of Group-III (isolated DN). The mean age (in years) was 57.7 ± 10.13, 53.15 ±10.48, and 54.15 ± 9.70 respectively in Group-I, II, and III. The mean duration of diabetes was 5.62 ± 4.99, 6.11 ± 3.72, 7.08 ± 5.20 years in Groups I, II and III, respectively. Diabetic retinopathy (DR) was significantly seen in Group-III DN (57.69%) followed by Group -II (29.62%) and absence of DR in Group-I (p=0.005). HbA1C level was significantly higher in Group-II (7.8 ±2.04 %) and Group-III (7.4% ±1.57 %) in than Group-I (6.8% ±1.58 %) (p=0.003). Nephrotic syndrome (NS) was the most frequent clinical manifestation in all groups. The most common histological types of NDRD were membranous nephropathy 8 (18.60%) cases followed by focal segmental glomerulosclerosis 5 (11.63%) cases, pauci-immune crescentic glomerulonephritis 5 (11.63%) cases and acute on chronic tubulointerstitial nephritis 5 (11.63%) cases. The most common histological types of coexisting NDRD and diabetic nephropathy were acute on chronic tubulointerstitial nephritis 11 (40.74%) cases followed by post infectious glomerulonephritis 5 (18.52%) cases. Conclusion: NDRD was diagnosed by renal biopsy in 70 (72.92%) patients out of 96 patients with type 2 DM, which confirms renal biopsy is gold standard for diagnosing NDRD in patients with T2D in patients.