Influence of baseline lipids on effectiveness of pravastatin in the CARE trial

Objectives. We sought to assess the influence of baseline lipid levels on coronary event rates and the effectiveness of pravastatin therapy in the Cholesterol And Recurrent Events (CARE) study. Background. The CARE study cohort provided a relatively unique opportunity to examine the relation between lipid levels and clinical events in a post-myocardial infarction (MI) population with relatively low cholesterol and low density lipoprotein (LDL) cholesterol values. Methods. There were 4,159 patients with a previous infarct and a total cholesterol level <240 mg/dl, LDL cholesterol level 115 to 174 mg/dl and triglyceride level <350 mg/dl randomly allocated to placebo (n = 2,078) or pravastatin 40 mg/day (n = 2,081). Time to either coronary death or nonfatal MI (primary end point) or to the secondary end point, which included undergoing a coronary revascularization procedure, was determined as a function of baseline lipids (total, LDL, high density lipoprotein [HDL] cholesterol and triglyceride levels). Results. Quartile analysis indicated important effects for LDL cholesterol, in which a higher LDL was associated with greater cardiac event rates (in the placebo group; every 25-mg/dl increment in LDL was associated with a 28% increased risk [5% to 56%, p = 0.015]) in the primary event. The differential event rates with respect to baseline LDL cholesterol for placebo and pravastatin groups reduced the difference in clinical outcomes at lower LDL cholesterol levels. In both the placebo and pravastatin groups, an inverse relation between baseline HDL cholesterol and cardiac events was observed (10 mg/d] lower baseline HDL cholesterol level was associated with a 10% [0% to 19%, p = 0.046] increase in coronary death or nonfatal MI). Conclusions. Within the LDL cholesterol levels in CARE (115 to 174 mg/dl), baseline values influenced both the risk of events in the placebo group as well as the clinical effectiveness of pravastatin therapy.