Kidney injury molecule-1 and cystatin C as early biomarkers for renal dysfunction in Iraqi type 2 diabetes mellitus patients

Diabetic kidney disease (DKD) is caused by a variety of processes. As a result, one biomarker is insufficient to represent the complete process. This study evaluated the diagnostic value of serum kidney injury molecule-1(KIM-1) and cystatin C (CysC) as early biochemical markers of DKD and predicted their sensitivities and specificities as biomarkers of nephropathy in Iraqi type 2 diabetic (T2DM) patients. This cross-sectional study includes 161 T2DM patients. Patients were divided according to urinary albumin creatinine ratio (ACR) such as group1: ACR≤ 30mg/g and group2: ACR> 30mg/g. Random spot urine and fasting blood samples were taken from each patient. Urinary ACR, blood glycated hemoglobin (HbA1c), and serum glucose, creatinine (SCr), lipid profile, CysC, and KIM-1 were assayed, and the estimated glomerular filtration rat (eGFR) was calculated. When compared to the normoalbuminuric group, the DKD group had significantly greater prevalence of retinopathy, and significantly elevated HbA1c and total cholesterol values. Also, DKD group had significantly greater serum levels of KIM-1 and CysC, and there was a significant positive correlation between them. In contrast, GFR was significantly higher in normoalbuminuric group and was significantly negatively correlated with both CysC and KIM-1. Multiple linear regression analysis found that there were a significant positive association among CysC and ACR. Receiver operating characteristic (ROC) analysis revealed that eGFR had the highest area under the curve (AUC=0.717), while SCr had the lowest AUC (0.556). In conclusion, serum KIM-1 and CysC levels could be considered as early biomarker for DKD along with eGFR. Additionally, there was a strong correlation between serum CysC and KIM-1 as well as other renal measures that indicate deteriorating kidney function.