Clinicopathological Features of Nondiabetic Renal Diseases from Different Age Groups: An Observational Cross-sectional Study

Background: Diabetes mellitus (DM) has become the leading cause of chronic kidney disease (CKD). Nondiabetic renal diseases (NDRDs) have different clinicopathological features and prognosis from those of diabetic nephropathy. Our study sought to analyze the clinical and pathological features of NDRDs, in different age groups through a cross-sectional study. Methods: All patients with type 2 DM at our center who underwent renal biopsy between March 1997 and March 2017 were screened and divided into three groups by age: Group 1 (youth group), 18–44 years old; Group 2 (middle-aged group), 45–59 years old; and Group 3 (elderly group), ≥60 years old. We analyzed the clinicopathological data and risk factors by univariate and multivariate logistic regression for NDRD of the patients to identify the features of NDRD in different age groups. Results: We included 982 patients in the final analysis. Patients with NDRD accounted for 64.4% of all patients. IgA nephropathy (IgAN) was the most common pathological pattern in young patients with NDRD, accounting for 26.3%. In the middle-aged group, the two most common pathological patterns were IgAN and membranous nephropathy. Membranous nephropathy was the most common pathological pattern in elderly patients with NDRD, accounting for 29.3%. Consistent with pathological features, glomerular hematuria is a risk factor for NDRD in Group 1 (odds ratio [OR], 26.514; 95% confidence interval [CI], 2.503–280.910; P = 0.006). On the other hand, rapidly increasing proteinuria or nephrotic syndrome is a risk factor for NDRD in Group 2 (OR, 5.921; 95% CI, 2.061–17.013; P = 0.001) and Group 3 (OR, 90.409; 95% CI, 6.198–1318.826; P = 0.001). Conclusions: This single-center study showed that the proportion and composition of NDRD differ among different age groups. Consistent with pathological features, some clinical indices such as hematuria and proteinuria showed different features among different age groups. Key words: Age; Nondiabetic Renal Disease; Type 2 Diabetic Nephropathy