Non-diabetic renal diseases in patients with diabetes mellitus clinicopathological correlation

Background and Aims: Non-diabetic renal diseases (NDRDs) form an important part of disease manifestations in patients with diabetes. Methods: This hospital-based prospective study was conducted to analyze incidence and spectrum of NDRDs in patients with diabetes with or without diabetic nephropathy (DN), effect of early specific interventions on outcome, and renal-retinal relationship in type 1 and type 2 diabetes mellitus with nephropathy. 44 Patients with T2DM with the clinical suspicion of NDRD were subjected to renal biopsy Renal biopsies were performed by using an automated biopsy gun. Tissue was processed for Light microscopy-LM and Immunofluorescence-IF. Electron Microscopy was done as and when required by reprocessing the tissue embedded in paraffin for LM. Biopsies were reported by one experienced renal pathologist. Results: Renal histopathology revealed that of 44 enrolled patients with clinically suspected NDRD, 61.4% had isolated NDRD, 13.6% had NDRD superimposed on DN, and 25% had isolated DN. The most common NDRDs were minimal change disease (19.2%) and DN + chronic pyelonephritis (33.3%) in patients with isolated NDRD, and NDRD superimposed on DN, respectively. In the DN group, no patient had proliferative diabetic retinopathy (PDR) or hypertensive retinopathy, 45.5% had nonproliferative diabetic retinopathy (NPDR) and 54.5% had no microangiopathy in retina. In the NDRD group, 9.1% each had PDR and hypertensive retinopathy, 36.4% had NPDR and 45.4% had no microangiopathy in retina. No patient in the DN group and 72.7% in the NDRD group received specific treatment. In hospital, dialysis support was provided to 27.3% and 21.2% of patients in the DN and NDRD groups, respectively. In the DN group, 72.7% of patients improved with conservative therapy, 18.2% were dependent on dialysis when discharged. One patient died during treatment. In the NDRD group, 78.8% showed recovery in the renal function and clinical improvement, 15.1% were dialysis dependent when discharged. Two patients died during treatment. Conclusion: Accurate diagnosis of underlying NDRD by kidney biopsy facilitates initiation of specific therapy, which may lead to clinical improvement in significant number of patients.