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

Background: Results of recent studies suggest that β-blockers are underused by elderly acute myocardial infarction (AMI) survivors. The goals of this study were to examine changes in post-AMI β-blocker use occurring between 1994 and 1997 and to identify factors associated with outpatient use of β-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, β-blocker usage rates were examined by year, and multivariate logistic regression was used to identify predictors of β-blocker use. Results: Post-AMI β-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 β-blocker than individuals who received all prescriptions from noncardiologists (odds ratio 1.52, P = .0001). Elderly patients who did not use β-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 β-blocker use, but persons using lipid-lowering agents were more likely to use β-blockers. Conclusions: Significant improvements in β-blocker use by elderly AMI survivors have occurred since 1994. Differences among physician specialties in β-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 β-blockers in elderly survivors of AMI, particularly those with heart failure.