Clinical utility of serum cystatin C in predicting coronary artery disease.

Background: There is limited data regarding the clinical utility of cystatin C in patients with stable coronary artery disease (CAD). The aim of this study was to determine the predictive value of cystatin C for the presence and severity of CAD and the association between this protein and other biochemical risk factors for atherosclerosis in patients with suspected CAD.

Methods: Ninety-four patients with CAD, and 92 patients without CAD but with cardiovascular risk factors, were included in this study. Echocardiography and other pertinent laboratory examinations were performed. Subjects were divided into four groups according to their cystatin C quartile. Cystatin C groups were analyzed for the association with CAD characteristics.

Results: The number of patients with CAD increased as the quartile of cystatin C increased, and there was a remarkable difference between quartiles (p < 0.001). Logistic regression analysis revealed independent predictors of incident CAD as cystatin C, hs-CRP, eGFR, HDL cholesterol and SBP (p = 0.005, p = 0.027, p = 0.017, p = 0.014 and p = 0.001, respectively). Moreover, cystatin C concentration was significantly correlated with CAD severity score (b = 0.258, p < 0.01). A cut-off value of 0.82 mg/L for cystatin C predicted incident CAD with a sensitivity and specificity of 75.5% and 75.0% respectively. Cystatin C concentration also correlated well with the atherosclerotic biochemical risk factors like homocysteine, creatinine and hs-CRP.

Conclusions: Cystatin C could be a useful laboratory tool in predicting the presence and severity of CAD in daily practice. It also correlates significantly with biochemical risk factors for CAD, namely homocysteine, low HDL and CRP.