Abstract

Objective: Investigated serum Cystatin C level and its clinical valuein predicting the glomerular filtration rate (GFR) in type 2 diabetic patients. Materials and methods: We studied on 115 healthy subjects with normal level of glucose and normal renal function, and 137 type 2 diabetic patients. We excluded the patients with thyroid dysfunction or taking glucocorticoid that affect the serum Cystatin level. The serum Cystatin C level measured in  both groups. In type 2 diabetic patients, we measured renal radiography, and estimated GFR by CKD.EPI formular. Diagnostic criteria of diabetes by ADA 2015. The diagnosis of CKD and decreased GFR by KDIGO 2012. Descriptive and cross-sectional study. Statistical analyses of data were performed on SPSS. Receiver operating characteristics (ROC) analysis, calculated the area under the curve (AUC) for serum Cystatin C.Binary logistic analysis of Cystatin C with risk factors for decreasing GFR. Results: -The level of serum Cystatin C  in type 2 diabetic patients  was significantly higher than control group (1,37±0,87; 0,84±0,09 mg/L, p<0.001, respectively). - The positively correlation was observed between eGFR according to CKD.EPI equation based on serum Cystatin C and renal radiography (r=0,818; p<0.001). The positively correlation between eGFR according to CKD.EPI equation based on serum Creatinine-Cystatin C and renal radiography (r=0,820; p<0.001). - Cystatin C has a high sensitivity, specificity and ROC in the prediction of decreased GFR < 60ml/min/1,73m2 according to radio-renogram (93.94%; 87.5%; ROC 0.936; p <0.001). - The increase of Cystatin C concentration is a independent risk factor for the prediction of decreasing GFR <60 ml / min /1.73m2. Binary logistic regression model: Logistic (GFR < 60 ml/min/1,73m2) = -7,968 + 3,841 x serum cystatin C. Conclusions: The serum Cystatin C level in type 2 diabetic patients was significantly higher than control group. There was possitivity correlation between eGFR based on Cystatin C and renal radiography. Serum cystatin C is superior to serum creatinine for prediction of decreased GFR. Serum Cystatin C is an indepent risk factor for predicting GFR.