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Abstract
Background
Placebo-controlled randomized trials have demonstrated the efficacy of selected β- blockers on outcomes in adults with heart failure, but the relative effectiveness of different β- blockers outside of the clinical trial setting is not well understood.
Methods and Results
We compared the 12-month risk of rehospitalization associated with receipt of different β-blockers among adults hospitalized for heart failure within two large not- for-profit health plans between January 1, 2001 and December 31, 2003. Exposure to β-blockers was ascertained from electronic pharmacy databases and readmissions within 12 months after discharge from the index hospitalization were identified from hospital discharge and billing claims databases. Demographic and clinical characteristics and receipt of other medications were identified from health plan administrative, ambulatory visit, hospital discharge, and pharmacy databases. Multivariable extended Cox regression was used to examine the association between receipt of different β-blockers and outcomes. We identified 11,396 adult members hospitalized for heart failure who had at least 12 months of continuous membership and drug benefit before the index hospitalization and during followup until being censored or experiencing an outcome event. During the analysis period between 2001 and 2003, there were 4877 person-years of exposure to β-blockers (37.7% atenolol, 44.8% metoprolol tartrate, 13.2% carvedilol, and 4.4% other). Crude rates of readmissions for heart failure were high overall during the first 12 months post-discharge (42.6 per 100 person-years) and did vary significantly among patients receiving different β-blockers (atenolol: 30.5; metoprolol tartrate: 45.3, and carvedilol 53.5). After adjustment for potential confounders, cumulative exposure to each β-blocker, and the propensity to receive carvedilol, the adjusted risks of readmission were not significantly different compared with atenolol for metoprolol tartrate (adjusted hazard ratio 0.97, 95% confidence interval [CI]: 0.87-1.08) or for carvedilol (adjusted hazard ratio 0.96, 95% CI: 0.78-1.18). Results were similar in analyses in the subgroup of patients receiving concurrent digoxin therapy, which was used as a proxy for reduced left ventricular systolic function and/or more severe heart failure.
Conclusions
In a contemporary cohort of high-risk patients hospitalized with heart failure, we found that the adjusted risks of rehospitalization for heart failure within 12 months were not significantly different among patients receiving atenolol, shorter-acting metoprolol tartrate or carvedilol.