Adverse outcomes of underuse of beta-blockers in elderly survivors of acute myocardial infarction
Soumerai, S.B.; McLaughlin, T.J.; Spiegelman, D.; Hertzmark, E.; Thibault, G.; Goldman, L.
JAMA 277(2): 115-121
1997
ISSN/ISBN: 0098-7484 PMID: 8990335 Document Number: 482795
Objectives: To study determinants and adverse outcomes (mortality and rehospitalization) of beta-blocker underuse in elderly patients with myocardial infarction; and whether the relative risks (RRs) of survival associated with beta-blocker use were comparable to those reported in the large randomized controlled trials (RCTs). Setting: New Jersey Medicare population. Design: Retrospective cohort design using linked Medicare and drug claims data from 1987 to 1992. Patients: Statewide cohort of 5332 elderly 30-day acute myocardial infarction (AMI) survivors with prescription drug coverage, of whom 3737 were eligible for beta-blockers. Main Outcome Measures: beta-Blocker and calcium channel blocker use in the first 90 days after discharge and mortality rates and cardiac hospital readmissions over the 2-year period after discharge, controlling for sociodemographic and base-line risk variables. Results: Only 21% of eligible patients received beta-blocker therapy; this rate remained unchanged from 1987 to 1991. Patients were almost 3 times more likely to receive a new prescription for a calcium channel blocker than for a new beta-blocker after their AMIs. Advanced age and calcium channel blocker use predicted underuse of beta-blockers. Controlling for other predictors of survival, the mortality rate among beta-blocker recipients was 43% less than that for nonrecipients (RR=0.57; 95% confidence interval (CI), 0.47-0.69). Effects on mortality were substantial in all age strata (65-74 years, 75-84 years, and gtoreq 85 years) and consistent with the results for elderly subgroups of 2 large RCTs. beta-Blocker recipients were rehospitalized 22% less often than nonrecipients (RR=0.78; 95% CI, 0.67-0.90). Use of a calcium channel blocker instead of a beta-blocker was associated with a doubled risk of death (RR= 1.98; 95% CI, 1.44-2.72), not because calcium channel blockers had a demonstrable adverse effect, but because they were substitutes for beta-blockers. Conclusions: beta-Blockers are underused in elderly AMI survivors, leading to measurable adverse outcomes. These data suggest that the survival benefits of beta-blockade after an AMI may extend to eligible patients older than 75 years, a group that has been excluded from RCTs.