Normal triglyceride levels and coronary artery disease events: the Baltimore Coronary Observational Long-Term Study

Abstract

Objectives: This study sought to evaluate long-term predictors of coronary events in men and women with arteriographically defined coronary artery disease (CAD).

Background: There is conflicting evidence of the role of triglycerides (TGs) as a prognosticator of CAD, and no studies have examined the long-term outcome of "normal" levels in predicting new coronary events.

Methods: This was a retrospective cohort study that evaluated 740 consecutive patients presenting for diagnostic coronary arteriography between 1977 and 1978. Beginning in 1988, patients with arteriographic CAD (n=350) were recontacted and asked to complete detailed medical questionnaires. Case and control patients were stratified by development of new coronary events, including death from ischemic heart disease, nonfatal myocardial infarction and revascularization.

Results: There were 199 events during the 18-year follow-up period. The mean high density lipoprotein cholesterol (HDL-C) was significantly lower (35 vs. 39 mg/dl; p=0.002) and TGs higher (160 vs. 137 mg/dl; p=0.03) in case patients than in control patients; After adjusting for age, gender and beta-adrenergic blocking agent use, multiple logistic regression analysis revealed the following independent predictors of CAD events: diabetes mellitus (relative risk [RR] 2.1, 95% confidence interval [CI] 1.4% to 3.1%), HDL-C <35 mg/dl (RR 1.5, 95% CI 1.1% to 2.00) and TGs >100 mg/dl (RR 1.5, 95% CI 1.1% to 2.1%). A Kaplan-Meier analysis revealed significantly reduced survival from CAD events in patients with baseline TG levels > or = 100 mg/dl compared with TG levels <100 mg/dl (p=0.008).

Conclusions: TG levels previously considered "normal" are predictive of new CAD events. The cutpoints established by the National Cholesterol Education Program for elevated TGs (>200 mg/dl) may need to be refined.