The use of cholesterol-lowering medications after coronary revascularization

In clinical trials, cholesterol-lowering medications have been proven to decrease mortality and morbidity and are strongly recommended as secondary prevention for patients with established coronary artery disease. Whether physicians and patients follow this recommendation is unknown. Our objective was to determine the rate at which patients fill at least one prescription for cholesterol-lowering medications after coronary revascularization.

Using the computerized administrative databases of the Régie de l'assurance maladie du Québec, we identified all elderly patients (older than 65 years) who had a coronary revascularization procedure (percutaneous coronary intervention or coronary artery bypass graft) between Apr. 1, 1995, and Dec. 31, 1997, and who survived until hospital discharge. We also determined the percentage of these patients who filled one or more prescriptions for cholesterol-lowering drug therapy before Dec. 31, 1999, or death, whichever date came first. We used multivariate logistic regression models to examine the independent associations between filling a prescription for a cholesterol-lowering drug, patient characteristics and the type and year of coronary revascularization.

We identified 11 958 elderly patients who had a coronary revascularization between Apr. 1, 1995, and Dec. 31, 1997. During a follow-up period that averaged 3 years, 4443 (37.2%) patients did not fill a prescription for a cholesterol-lowering medication. Patients who were male, of advanced age, who had diabetes or congestive heart failure were less likely to fill a prescription for a cholesterol-lowering medication. Patients whose initial revascularization procedure was coronary artery bypass grafting were also less likely than those who had angioplasty to start cholesterol-lowering medication (relative risk [RR] 0.77, 95% confidence interval [CI] 0.73 - 0.81). Use of cholesterol lowering medications before the revascularization procedure was very strongly associated with future drug use (RR 7.20, 95% CI 6.83-7.58).

In this population-based study of revascularized patients, we observed a substantial underutilization of cholesterol-lowering medications after revascularization. Our observations suggest an important role for continuity of care in the treatment of cardiovascular patients undergoing revascularization procedures.