Biomarkers for Early Detection of Diabetic Kidney Disease

Abstract

 Background: Diabetic kidney disease (DKD) contributes substantially to chronic kidney disease and kidney failure. Conventional screening relies on urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR), although early tubular and glomerular alterations can be incompletely reflected by these measurements. Serum cystatin C, urinary neutrophil gelatinase-associated lipocalin (NGAL), and urinary kidney injury molecule-1 (KIM-1) are candidate complementary biomarkers. Objective: To evaluate the association of selected biomarkers with moderately increased albuminuria in patients with type 2 diabetes mellitus and assess their ability to discriminate between albuminuria categories. Materials and Methods: A hospital-based, cross-sectional observational framework included 96 adults with type 2 diabetes mellitus at the Department of General Medicine, Dr. N.D. Desai Faculty of Medical Science and Research, Nadiad, Gujarat, from September 2025 to February 2026. Participants were categorized by UACR as Group A (<30 mg/g) or Group B (30–299 mg/g), with eGFR ≥60 mL/min/1.73 m². Clinical characteristics, serum creatinine, HbA1c, eGFR, serum cystatin C, urinary NGAL, and urinary KIM-1 were evaluated using group comparisons, correlations, receiver operating characteristic (ROC) analysis, and regression models. Results: Of the 96 participants, 58 (60.4%) were classified in Group A and 38 (39.6%) in Group B. Group B had longer diabetes duration, higher HbA1c, and lower eGFR. Median serum cystatin C was 1.04 versus 0.82 mg/L (p<0.001); urinary NGAL was 48.39 versus 30.21 ng/mg creatinine (p<0.001); and urinary KIM-1 was 164.04 versus 106.95 pg/mg creatinine (p<0.001). The ROC AUCs were 0.831, 0.767, and 0.736, respectively. All three biomarkers correlated positively with UACR. Conclusion: Higher concentrations of serum cystatin C, urinary NGAL, and urinary KIM-1 were associated with moderately increased albuminuria in this cross-sectional study framework. Longitudinal validation is required to establish whether these biomarkers predict deterioration in kidney function or add clinical value beyond UACR and eGFR.