Changes in rates of beta-blocker use between 1994 and 1997 among elderly survivors of acute myocardial infarction

Abstract

Background: Results of recent studies suggest that beta-blockers are underused by elderly acute myocardial infarction (AMI) survivors. The goals of this study were to examine changes in post-AMI beta-blocker use occurring between 1994 and 1997 and to identify factors associated with outpatient use of beta-blockers.

Methods: Patients included 9534 individuals >/=65 years of age who were enrolled in Pennsylvania's Pharmaceutical Assistance Contract for the Elderly (PACE) and who survived AMI between 1994 and 1997. With the use of outpatient prescription claims, beta-blocker usage rates were examined by year, and multivariate logistic regression was used to identify predictors of beta-blocker use.

Results: Post-AMI beta-blocker use increased from 39.6% in 1994 to 58.6% in 1997. Controlling for AMI year, individuals who had any prescriptions written by a cardiologist were more likely to use a beta-blocker than individuals who received all prescriptions from noncardiologists (odds ratio 1.52, P =.0001). Elderly patients who did not use beta-blockers tended to have greater severity of illness, non-Q-wave infarctions, atrial fibrillation, and comorbidities such as congestive heart failure, chronic obstructive pulmonary disease, and asthma. Use of calcium channel blockers and diuretics was negatively associated with beta-blocker use, but persons using lipid-lowering agents were more likely to use beta-blockers.

Conclusions: Significant improvements in beta-blocker use by elderly AMI survivors have occurred since 1994. Differences among physician specialties in beta-blocker prescribing appear to remain. Across all prescriber specialties, historic contraindications constitute major factors in the choice of post-AMI therapy. Further efforts should be made to encourage the use of beta-blockers in elderly survivors of AMI, particularly those with heart failure.