Cystatin C and the Risk for Cardiovascular Events in Patients With Asymptomatic Carotid Atherosclerosis

BACKGROUND AND PURPOSE: Renal dysfunction is a risk factor for cardiovascular events in patients with atherosclerosis. Unlike serum creatinine or estimated glomerular filtration rate, cystatin C reflects renal dysfunction independent of factors such as sex, weight, and race. We investigated whether baseline serum levels of cystatin C predict major cardiovascular events in patients with asymptomatic carotid atherosclerosis and compared the predictive value of cystatin C to these established markers of renal function. METHODS: We prospectively studied 1004 of 1286 consecutive patients with carotid ultrasound scanning. Patients were followed for the occurrence of major cardiovascular events, a composite of myocardial infarction, percutaneous coronary intervention, coronary bypass graft, stroke, and death. RESULTS: During a median of 3 years of follow-up, we recorded 346 major cardiovascular events in 311 patients. The risk for a first major cardiovascular event increased significantly with increasing quintiles of cystatin C; hazard ratios ranged from 1.18 to 1.94 for the highest versus the lowest quintile (P<0.001 for trend). Creatinine levels showed no significant association with major cardiovascular events, and for glomerular filtration rate, only the lowest quintile was moderately associated with adverse cardiovascular outcome. CONCLUSIONS: Cystatin C was significantly and gradually associated with future cardiovascular events in patients with carotid atherosclerosis. In contrast, neither serum creatinine nor estimated glomerular filtration rate were significant predictors of adverse cardiovascular outcomes.