Lipoprotein(a) for Risk Assessment in Patients With Established Coronary Artery Disease

Objectives The purpose of this study was to assess the prognostic utility of lipoprotein(a) [Lp(a)] in individuals with coronary artery disease (CAD). Background Data regarding an association between Lp(a) and cardiovascular (CV) risk in secondary prevention populations are sparse. Methods Plasma Lp(a) was measured in 6,708 subjects with CAD from 3 studies; data were then combined with 8 previously published studies for a total of 18,978 subjects. Results Across the 3 studies, increasing levels of Lp(a) were not associated with the risk of CV events when modeled as a continuous variable (odds ratio [OR]: 1.03 per log-transformed SD, 95% confidence interval [CI]: 0.96 to 1.11) or by quintile (Q5:Q1 OR: 1.05, 95% CI: 0.83 to 1.34). When data were combined with previously published studies of Lp(a) in secondary prevention, subjects with Lp(a) levels in the highest quantile were at increased risk of CV events (OR: 1.40, 95% CI: 1.15 to 1.71), but with significant between-study heterogeneity (p = 0.001). When stratified on the basis of low-density lipoprotein (LDL) cholesterol, the association between Lp(a) and CV events was significant in studies in which average LDL cholesterol was ≥130 mg/dl (OR: 1.46, 95% CI: 1.23 to 1.73, p  Conclusions Lp(a) is significantly associated with the risk of CV events in patients with established CAD; however, there exists marked heterogeneity across trials. In particular, the prognostic value of Lp(a) in patients with low cholesterol levels remains unclear.