The beneficial effect of statin drugs in preventing myocardial infarction and other coronary events in patients with dyslipidemia is well known. Study results indicate that statin drugs lower the serum level of C-reactive protein (CRP) and may have anti-inflammatory properties. Inflammatory processes are believed to play a role in the conversion of coronary vessel-wall lipids into dangerous atheromatous plaques. Ridker and colleagues describe the effects of lovastatin on CRP and the associated preventive effect against coronary ischemia.
During a five-year trial of lovastatin therapy, the investigators measured serum CRP levels at study entry and one year later in 5,742 men and women. Study subjects were randomly assigned to receive either lovastatin (20 mg per day) or placebo and were followed for an average of 5.2 years for the subsequent occurrence of first acute coronary events (myocardial infarction, unstable angina, or sudden cardiac death).
Statistical analysis demonstrated that CRP and lipid levels varied independently before and during treatment. A baseline elevation in lipids did not predict an elevated CRP level, and a reduction in lipids after statin therapy did not predict that CRP would be decreased. As anticipated, treatment with lovastatin effectively prevented coronary events in patients whose baseline ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol was higher than the median ratio. Treatment with lovastatin also reduced serum CRP by an average of 15 percent, and there was an association between lower levels of CRP and reduced numbers of coronary events.
In the subgroup of patients with elevated low-density lipoprotein (LDL) levels and no elevation in CRP, the risk of coronary events was reduced by 62 percent. The group with below-average LDL and elevated CRP levels had a risk reduction of 42 percent. Patients with both lipid and CRP levels below the median did not benefit from the use of lovastatin.
The authors conclude that their study confirms the effectiveness of statin therapy in reducing coronary events in patients with elevated lipid levels, and that a retrospective analysis of the data suggests another independent protective effect related to reductions in serum CRP, even in patients without elevated lipid levels.