Abstract 15919: Beta Blockers Confer a Survival Benefit in Patients With Myocardial Infarction
BACKGROUND: The studies demonstrating mortality benefits of beta blockers (BB) after myocardial infarction (MI) were conducted before the era of percutaneous intervention and widespread use of statins. Recent high-profile literature examined BB use in patients with prior MI and found no benefit in composite cardiovascular outcomes or mortality. However, this work did not account for medication changes over time, patient non-adherence, or race-BB interaction. We evaluated the association of death and rehospitalization with time-varying BB exposure in patients with MI.
METHODS: This retrospective cohort study included all patients who presented with MI at a single health care system who also had health insurance under our covered entity from January 1, 1997 to June 30, 2011. Pharmacy claims were used to estimate BB exposure over six-month rolling windows, calculated as the continuous multiple-interval medication availability. The primary endpoint was all-cause death, and the secondary endpoint was all-cause rehospitalization. The effect to BB exposure was tested using time-updated Cox proportional hazards models adjusted for potential confounding factors (demographics, laboratories, comorbidities, as well as angiotensin-converting enzyme inhibitors (ACEI) / angiotensin receptor blockers (ARB), statin, and adenosine diphosphate (ADP)-antagonist exposure).
RESULTS: We identified 7339 patients with prior MI and the following characteristics: mean age 66.5±3.5 years, 56.3% male, 39.3% African American, 32.6% chronic renal failure, 39.2% peripheral vascular disease, 40.7% heart failure (HF), and 46.0% diabetes mellitus. Median follow-up was 3.1 years. In adjusted models, BB exposure was associated with a 30% relative risk reduction in all-cause death (hazard ratio [HR] 0.70, p=0.005) and a 51% relative risk reduction (p=0.001) when excluding patients with HF. ACEI/ARB (HR 0.77, p=0.004), statins (HR 0.45, p=0.001), and ADP-antagonist therapy (HR 0.52, p=0.001) were also significant in reducing all-cause death. BB exposure was also associated with a reduced risk of all-cause rehospitalization (HR 0.76, p=0.042).
CONCLUSIONS: Among patients who have suffered MI, BB are associated with reduced all-cause death and hospitalization.
- © 2013 by American Heart Association, Inc.