Background: Although lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) levels are associated with cardiovascular events, Lp-PLA(2) is physically linked to LDL cholesterol (LDL-C). Whether measures of Lp-PLA(2) mass or activity continue to predict risk after LDL-C reduction by statin therapy is uncertain.
Methods: Lp-PLA(2) mass concentration and activity were evaluated at baseline and after treatment in the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial comparing rosuvastatin 20 mg to placebo among 17 802 men and women without cardiovascular disease or diabetes at study entry. The relationships of Lp-PLA(2) mass and activity with risk of future vascular events were evaluated in the placebo and rosuvastatin groups.
Results: Before randomization, levels of Lp-PLA(2) mass and activity correlated moderately with each other and with LDL-C. The magnitude of these correlations increased after statin therapy. Rosuvastatin reduced Lp-PLA(2) mass by 33.8%, Lp-PLA(2) activity by 33.2%, and LDL-C by 48.7% (all P < 0.0001). Among those study participants allocated to placebo, increasing quartiles of Lp-PLA(2) activity (P(trend) = 0.04) but not Lp-PLA(2) mass (P(trend) = 0.92) were associated with incident cardiovascular events after adjustment for LDL-C and conventional risk factors. Comparable analyses conducted among those allocated to rosuvastatin revealed no significant relationship between Lp-PLA(2) levels and subsequent vascular events. The ability of rosuvastatin to reduce vascular events was not significantly modified by baseline Lp-PLA(2) level.
Conclusions: Among JUPITER trial participants allocated to placebo, levels of Lp-PLA(2) activity, but not mass, were associated with cardiovascular risk. However, Lp-PLA(2) no longer predicted risk or modified clinical outcomes when participants were treated with rosuvastatin.