Determination of Clinical Cut-Off Values for Serum Cystatin C Levels to Predict Ischemic Stroke Risk

Background: The association between cystatin C and risk of ischemic stroke is inconsistent and the cut-off values of cystatin C are diverse in different articles. We aimed to investigate the association between cystatin C levels and the development of ischemic stroke and to explore the clinical cut-off values of serum cystatin C levels for ischemic stroke. Methods: This prospective cohort study included 7658 participants from the China Health and Retirement Longitudinal Study who were free of cardiovascular diseases and cancer at baseline. A decision-tree model was used to find reasonable cut-off values for cystatin C levels. Logistic regression models were used to analyze the association between different levels of cystatin C and the risk of ischemic stroke. Results: The whole cohort was divided into the following 3 groups according to the decision tree: group-low (<.901 mg/L), group-moderate (.901～1.235 mg/L), and group-high (>1.235 mg/L). After 4 years of follow-up, we identified 156 cases of ischemic stroke. After adjusting for potential confounding factors, the odds ratios (95% confidence intervals) of ischemic stroke were 1.637 (1.048-2.556) for group-moderate and 2.326 (1.285-4.210) for group-high) compared with the low group of cystatin C. Subgroup analyses showed that the association between cystatin C levels and the incidence of ischemic stroke was more pronounced in males or old people than in females or young people. Conclusions: We found 2 suitable cut-off values for serum cystatin C levels and found that high levels of cystatin C were associated with an increased risk of ischemic stroke.