(HealthDay News) – Lipoprotein (a) (Lp[a]) has utility in assessing cardiovascular risk in patients with coronary artery disease (CAD); however, the prognostic value of Lp(a) in patients with low cholesterol levels remains unclear, according to a study published online Oct. 23 in the Journal of the American College of Cardiology.
Michelle O’Donoghue, M.D., from Brigham and Women’s Hospital in Boston, and colleagues combined data from three studies of patients with CAD (6,762 participants) and eight previously published studies in which plasma Lp(a) was measured (for a total of 18,979 patients).
The researchers found that increasing levels of Lp(a) were not associated with cardiovascular event risk when modeled as a continuous variable (OR, 1.03) or by quintile (OR Q5:Q1, 1.05), based on data from the three studies. Utilizing the total combined data, subjects with Lp(a) levels in the highest quintile were at increased risk of cardiovascular events (OR, 1.4); however, there was significant between-study heterogeneity (P=0.001). The association between Lp(a) and cardiovascular events, when stratified on the basis of low-density lipoprotein (LDL) cholesterol, was significant in studies in which average LDL cholesterol was ≥130 mg/dL (OR, 1.46; P<0.001), whereas this relationship was not significant for studies with an average LDL cholesterol <130mg/dL (OR, 1.2; P=0.21).
“Lp(a) is significantly associated with the risk of cardiovascular events in patients with established CAD; however, there exists marked heterogeneity across trials,” O’Donoghue and colleagues conclude. “In particular, the prognostic value of Lp(a) in patients with low cholesterol levels remains unclear.”
Several authors disclosed financial ties to the pharmaceutical industry, including companies that funded some studies included in the meta-analysis.