Evaluation of Serum Cystatin C levels in Type 2 Diabetes Mellitus Patients with and without Diabetic Nephropathy: A Cross-sectional Study

Introduction: Diabetes Mellitus (DM) is a metabolic disorder characterised by insufficient insulin secretion or action that raises blood glucose levels. One of DM’s major chronic complications is Diabetic Nephropathy (DN), a leading cause of End-Stage Renal Disease (ESRD). Early diagnosis of renal dysfunction is a major clinical challenge. Cystatin C is a low molecular weight protein, proposed for the evaluation of renal function. Aim: To estimate the level of serum Cystatin C in Type 2 DM (T2DM) with and without DN. Materials and Methods: The present cross-sectional study was done in the Department of Biochemistry and Nephrology, Regional Institute of Medical Sciences, Imphal, Manipur, India, from March 2023 to March 2025. A total of 153 diabetic individuals ≥18 years were included in the study, classified into three groups based on Urinary Albumin Excretion (UAE): Normoalbuminuria, Microalbuminuria, and Macroalbuminuria. Serum Cystatin C level was measured using a sandwich Enzyme-Linked Immunosorbent Assay (ELISA). Age, gender, Body Mass Index (BMI), and weight were analysed to identify associations with DN. The Pearson’s correlation coefficient was used to determine the association of Cystatin C levels with albuminuria. The p-value of <0.05 was considered significant. Results: Age differed significantly (p<0.001), being highest in the normoalbuminuria group. Body weight (p=0.24), height (p=0.51), and BMI (p=0.24) showed no significant group differences in all three groups. Serum Cystatin C levels were much higher in microalbuminuria and macroalbuminuria compared to normoalbuminuria, and the difference was statistically significant (p<0.001). A significant positive correlation was noted between serum Cystatin C and UAE (r=0.686, p<0.001). Conclusion: The study found significant differences in Serum cystatin C in normoalbuminuria, microalbuminuria, and macroalbuminuria DM patients. So, Serum cystatin may exhibit great promise for DN risk assessment and early identification.