Clinical predictors differentiating non-diabetic renal diseases from diabetic nephropathy in a large population of type 2 diabetes patients

•This study included a large sample of type 2 DM patients who underwent renal biopsy.•We included only patients with either DN or a NDRD to decrease confounding factors.•Clinical characteristics of NDRD patients was evaluated objectively.•Absence of retinopathy achieved the overall highest diagnostic efficiency.

AimsNon-diabetic renal diseases (NDRDs) are associated with better renal outcomes than diabetic nephropathy (DN). This study was conducted to determine the common clinical markers predicting NDRDs in type 2 diabetes patients.MethodsPatients with type 2 diabetes mellitus who underwent a renal biopsy were screened. Eligible patients were categorized into two groups: DN group and NDRD group. Patient's clinical characteristics and laboratory data were collected. Logistic regression analysis was performed to identify risk factors for NDRD development, and the diagnostic performance of these variables was evaluated.ResultsThe study included 248 patients, 96 (38.71%) in the DN group and 152 (61.29%) in the NDRD group. Patients in the NDRD group had a shorter duration of DM and higher hemoglobin, estimated glomerular filtration rate, and urine osmotic pressure values as well as a higher incidence of glomerular hematuria than patients in the DN group. In the NDRD patients, the most common pathological type was membranous nephropathy (55, 36.18%). Absence of retinopathy (OR, 44.696, 95% CI, 15.91-125.566), glomerular hematuria (OR, 9.587, 95% CI, 2.027-45.333), and DM history ⩽5 years (OR, 4.636, 95% CI, 1.721-12.486) were significant and independent risk factors for the development of NDRD (P < 0.01). Absence of retinopathy achieved the overall highest diagnostic efficiency with a sensitivity of 92.11% and specificity of 82.29%. Glomerular hematuria had the highest specificity (93.75%).ConclusionShorter duration of diabetes (⩽5 years), absence of retinopathy, and presence of glomerular hematuria were independent indicators associated with NDRDs, indicating the need for renal biopsy.