Prognosis and reclassification by ykl-40 in stable coronary artery disease

Abstract

Background-—The inflammatory biomarker YKL-40 has previously been studied as a potential risk marker in cardiovascular disease. We aimed to assess the prognostic reclassification potential of serum YKL-40 in patients with stable coronary artery disease. Methods and Results-—The main study population was the placebo group of the CLARICOR (Effect of Clarithromycin on Mortality and Morbidity in Patients With Ischemic Heart Disease) trial. The primary outcome was a composite of acute myocardial infarction, unstable angina pectoris, cerebrovascular disease, and all-cause mortality. We used Cox proportional hazards regression models adjusted for C-reactive protein level and baseline cardiovascular risk factors. Improvement in prediction by adding serum YKL-40 to the risk factors was calculated using the Cox-Breslow method and c-statistic. A total of 2200 patients were randomized to placebo, with a follow-up duration of 10 years. YKL-40 was associated with an increased risk of the composite outcome (hazard ratio per unit increase in (YKL-40) 1.13, 95% CI 1.03–1.24, P=0.013) and all-cause mortality (hazard ratio 1.32, 95% CI 1.17–1.49, P<0.0001). Considering whether a composite-outcome event was more likely to have, or not have, occurred to date, we found 68.4% of such predictions to be correct when based on the standard predictors, and 68.5% when serum YKL-40 was added as a predictor. Equivalent results were obtained with c-statistics. Conclusions-—Higher serum YKL-40 was independently associated with an increased risk of adverse cardiovascular outcomes and mortality. Addition of YKL-40 did not improve risk prediction in patients with stable coronary artery disease.