National use and effectiveness of beta-blockers for the treatment of elderly patients after acute myocardial infarction: National Cooperative Cardiovascular Project
Krumholz, H.M.; Radford, M.J.; Wang, Y.; Chen, J.; Heiat, A.; Marciniak, T.A.
JAMA 280(7): 623-629
1998
ISSN/ISBN: 0098-7484 PMID: 9718054 Document Number: 491076
Context.-Despite the importance of beta-blockers for secondary prevention after acute myocardial infarction (AMI), several studies have suggested that they are substantially underutilized, particularly in older patients. Objectives.-To describe the contemporary national pattern of beta-blocker prescription at hospital discharge among patients aged 65 years or older with an AMI, to identify the most important predictors of the prescribed use of beta-blockers at discharge, and to determine the independent association between beta-blockers at discharge and mortality in clinical practice. Design.-Retrospective cohort study using data created from medical charts and administrative files. Setting.-Acute care nongovernmental hospitals in the United States. Patients.-National cohort of 115015 eligible patients aged 65 years or older who survived hospitalization with a confirmed AMI in 1994 or 1995. Main Outcome Measures.-beta-Blocker as a discharge medication and mortality in the year after discharge. Results.-Among the 45 308 patients without contraindications to beta-blockers, 22 665 (50.0%) had a beta-blocker as a discharge medication. There was significant variation by state, ranging from 30.3% to 77.1 %. Of the 36 795 patients who were not receiving beta-blocker therapy on admission, 16 006 (43.5%) had therapy initiated on or before discharge. Demographic and clinical variables explained relatively little of the variation in the initiation of beta-blocker therapy. The prescribed use of calcium channel blockers at discharge had a strong negative association with the use of beta-blockers (odds ratio (OR) of beta-blocker use, 0.25; 95% confidence interval (CI), 0.24-0.26). The New England region had significantly higher use of beta-blocker therapy than the rest of the country. Compared with cardiologists, internists had, similar rates (OR, 0.94; 95% CI, 0.90-1.00) and general and family practice physicians had lower rates (OR, 0.78; 95% CI, 0.73-0.83). After adjusting for potential confounders, beta-blockers were associated with a 14% lower risk of mortality at 1 year after discharge. The association with lower mortality was present in subgroups stratified by age, sex, and left ventricular ejection fraction. Conclusions.-Many ideal patients for beta-blocker therapy are not prescribed these drugs at discharge following AMI. The clinical and/demographic characteristics of the patients do not explain much of the variation in the treatment pattern. Geographic factors and physician specialty are independently associated with the decision to use beta-blockers. Elderly patients who are prescribed beta-blockers at discharge have a better survival rate, consistent with the findings of randomized controlled trials of younger and lower-risk populations.