Background: Patients with coronary artery disease (CAD) are at considerable risk for subsequent cardiovascular events. Although hyperlipidemia accentuates the risk, predictors of subsequent events with CAD and desirable total cholesterol (TC) (less than 5.2 mmol/l) have not been assessed.
Methods and results: A survival analysis was performed in a subset of 740 consecutive patients who underwent diagnostic coronary arteriography between 1977 and 1978. Eight-three men and 24 women with angiographically documented CAD and desirable TC were followed for subsequent cardiovascular events, including myocardial infarction and cardiovascular death. Over a 13-year period, 75% of CAD subjects with reduced high density lipoprotein cholesterol (HDL-C) (less than 0.9 mmol/l) developed a subsequent cardiovascular event compared with 45% of those with HDL-C greater than or equal to 0.9 mmol/l (p = 0.002). A Kaplan-Meier analysis revealed significantly greater survival from cardiovascular end points in patients with baseline levels of HDL-C greater than or equal to 0.9 mmol/l (p = 0.005). After 11 variables were tested, an age-adjusted Cox proportional-hazards model identified two pairs of independent predictors of subsequent cardiovascular events: they were a left ventricular ejection fraction (LVEF) less than 35% (relative risk [RR], 6.5; 95% confidence interval [CI], 2.8, 15.3; p less than 0.001) and reduced HDL-C (RR, 2.0; 95% CI, 1.2, 3.3; p = 0.01) in the first model and LVEF less than 35% (RR, 6.5; 95% CI, 2.7, 15.6; p less than 0.001) and TC:HDL ratio greater than or equal to 5.5 (RR, 1.9; 95% CI, 1.1, 3.1; p = 0.02) in the second model.
Conclusions: Low HDL-C (or high TC:HDL-C) is strongly predictive of subsequent cardiovascular events in subjects with CAD, despite desirable TC. As such, identification of this potentially modifiable risk factor should be actively pursued in this high-risk subgroup.