Circulating oxidized LDL is a useful marker for identifying patients with coronary artery disease

Our aim was to determine the usefulness of circulating oxidized low density lipoprotein (LDL) in the identification of patients with coronary artery disease (CAD). A total of 304 subjects were studied: 178 patients with angiographically proven CAD and 126 age-matched subjects without clinical evidence of cardiovascular disease. The Global Risk Assessment Score (GRAS) was calculated on the basis of age, total and high density lipoprotein cholesterol, blood pressure, diabetes mellitus, and smoking. Levels of circulating oxidized LDL were measured in a monoclonal antibody 4E6-based competition ELISA. Compared with control subjects, CAD patients had higher levels of circulating oxidized LDL (P<0.001) and a higher GRAS (P<0.001). The sensitivity for CAD was 76% for circulating oxidized LDL (55% for men and 81% for women) compared with 20% (24% for men and 12% for women) for GRAS, with a specificity of 90%. Logistic regression analysis revealed that the predictive value of oxidized LDL was additive to that of GRAS (P<0.001). Ninety-four percent of the subjects with high (exceeding the 90th percentile of distribution in control subjects) circulating oxidized LDL and high GRAS had CAD (94% of the men and 100% of the women). Thus, circulating oxidized LDL is a sensitive marker of CAD. Addition of oxidized LDL to the established risk factors may improve cardiovascular risk prediction.