Serum Homocysteine, cystatin C as Biomarkers for Progression of Diabetic Nephropathy

Objective To investigate the clinical efficacy of serological level homocysteine (Hcy) and cystatin C (Cys-C) as biomarkers for progression of diabetic nephropathy (DN). Methods Seventy-five patients with type 2 diabetes mellitus (DM) hospitalized in Lishui People’s Hospital from January 2015 to May 2018 were included in the present study. Of the 75 cases, 28 were simple DM, 25 were early stage DN (DNe) and other 22 subjects were clinical stage DN (DNc). The serum level of Hcy and Cys-C were detected and compared among the DM, DNe and DNc groups. The efficacy of serological levels of Hcy, and Cys-C as biomarkers for diagnosis of early stage diabetic nephropathy was calculated. Results The serological levels of Hcy were 11.53±3.05 μmol/L, 15.39±4.58 μmol/L and 18.14±7.03 μmol/L for DM, DNe and DNc groups respectively (P<0.001). Serum level of Cys-C, were 0.89±0.23 mg/L, 1.51±0.60 mg/L and 2.63±0.90 mg/L respectively for DM, DNe and DNc groups respectively (P<0.001). Significant positive correlation between serum Cys-C and Hcy was detected in DNe (rpearson=0.55, P=0.004) and DNc (rpearson=0.44, P=0.04) groups. However, there was no significant correlation of serological Cys-C and Hcy in DM group (rpearson=0.08, P=0.70). The sensitivity and specificity in diagnosis of early stage DN were 76.0 (95%CI:54.87-90.64)%, 64.29 (544.07-81.36)% for serological Hcy and 80.0 (559.30-93.17)%, 89.29 (571.77-97.73)% for serum Cys-C respectively. The diagnostic area under the ROC curve (AUC) was 0.76 (0.63 to 0.90) and 0.84 (0.72-0.96) respectively for serum Hcy and Cys-C in detection early stage DN. Conclusion: Serum levels of Hcy and Cys-C in diabetic nephropathy patients were elevated compared to that of simple DM cases, making them potential biomarkers for diagnosis of early DN from DM patients.