CORRELATION BETWEEN CLINICAL AND PATHOLOGIC FEATURES OF DIABETIC NEPHROPATHY

Abstract

Background: Diabetic nephropathy is the most common cause of end stage renal disease in Thailand. Renal biopsy remains the gold standard investigation to diagnose and classify diabetic nephropathy. Objectives: In this study, we aimed to evaluate the correlation between clinical parameters and renal pathology classification among patients with type 2 diabetic and nephropathy. Methods: We conducted an observational study and enrolled 63 patients undergoing renal biopsy between 1 January 2014 and 31 December 2018. Pathologic classification established by the Renal Pathology Society was used to assess the severity of histologic lesions in diabetic nephropathy. Clinical parameters including age, sex, duration, presence of diabetic retinopathy, blood urea nitrogen, creatinine, urine protein creatinine ratio, fasting plasma glucose and hemoglobin A1C were collected. Results: At the time of biopsy, mean age was 50.25±11.46 years. Median duration of diabetes mellitus was 10 years with interquartile range (IQR) 3.75-12.00 years, mean serum creatinine was 2.44 ± 1.31 mg/dL and estimated glomerular filtration rate was 22.41±12.16 mL/min/1.73 m2. Based on the glomerular classification, 1 patient (1.6%) was in class I, 16 (25.3%) in class II, 25 (39.7%) in class III and 21 (33.3%) in class IV. Using multivariate analysis, class IV was associated with rising serum creatinine compared with class II [adjusted odds ratio (AOR)= 2.58; 95% CI= 1.13-5.89]. Patients with interstitial fibrosis and tubular atrophy (IFTA) <25%, 25-50% and >50% were observed in 10, 27 and 22 patients, respectively. Patients with IFTA >50% were significantly associated with duration of diabetes (OR=1.27; 95%CI=1.21-1.57), serum creatinine (OR=3.92; 95%CI=1.34-11.48) and urine protein (OR= 1.25; 95%CI=1.01-1.55) compared with patients with IFA<25%. Using multivariate analysis, only serum creatinine (AOR=3.48; 95%CI=1.23-12.65) was confirmed as independently correlated to IFTA >50% compared with IFTA <25%. A univariate analysis revealed no significant correlation between vascular indexes and renal function. Conclusion: The results revealed that advanced glomerular lesions and high IFTA >50% correlated with impaired renal function in type 2 diabetic nephropathy