CST3 and chronic kidney disease: A total of 1042 patients were included in the final analysis (mean age 62.87 ± 10.35 years, mean creatinine clearance rate 75.12 ± 26.24 mL/min, and mean cystatin C 1.20 ± 0.47 mg/L), and 297(28.5%) patients presented with pre-existing chronic kidney disease (CKD), creatinine clearance <60 ml/min.