Predictive Ability of Interstitial Fibrosis and Tubular Atrophy Scoring in Determining the Severity of Diabetic Kidney Disease: A Cross-sectional Study

Abstract

Introduction: Diabetic Kidney Disease (DKD) is a major complication of Diabetes Mellitus (DM). Renal biopsy is the gold standard for the diagnosis and management of many renal diseases. Renal Interstitial Fibrosis and Tubular Atrophy (IFTA), as well as the number of obsolescent glomeruli, are prognostic factors associated with Diabetic Nephropathy (DN). Aim: To describe the renal biopsy profile of patients with DM presenting with renal disease and to determine the significance of IFTA scoring and the number of obsolescent glomeruli in predicting DKD and its severity. Materials and Methods: This cross-sectional study was conducted over a period of three years, from 2019 to 2022, involving a total of 189 patients selected through purposive sampling. Patients with DM who presented with renal disease and required renal biopsy to confirm the diagnosis were admitted to the Department of General Medicine and Nephrology at Kempegowda Institute of Medical Sciences Hospital and Research Centre, Bengaluru, Karnataka, India. The biopsy reports were obtained and analysed. Data were analysed using Statistical Package for the Social Sciences (SPSS) version 20.0 and results were expressed using descriptive and inferential statistics. A p-value of <0.05 was considered statistically significant. Results: The mean age of the participants was 53.02±11.00 years, with an age range from 21 to 81 years. Among the subjects, 78.3% were males and 21.7 were females. Based on the renal biopsy findings, DN was the most common condition, found in 127 subjects (67.6%). Nearly 50.0% of those with DN had Class IV chronic DN, followed by Class III (42.5%). Chronic interstitial nephritis was the most common Non Diabetic Kidney Disease (NDKD), accounting for 24.6% of cases. IFTA scoring was significantly associated with DKD and there was a significant positive correlation between the severity of IFTA scores and the number of obsolescent glomeruli with the class of DKD. A unit rise in the IFTA score and the number of obsolescent glomeruli increased the risk of having severe DKD (Class III and Class IV) by 4.32 times and 1.24 times, respectively, compared to those with less severe forms (Class I and II) (p<0.05). Conclusion: The IFTA scoring and the number of obsolescent glomeruli were found to be significant independent predictors of the severity of DKD.

Keywords

• diabetic glomerulosclerosis
• intracapillary glomerulosclerosis
• kimmelstiel-wilson disease
• nephropathy
• nodular glomerulosclerosis