Association of β-blocker exposure with outcomes in heart failure differs between African American and white patients.

BACKGROUND: β-Blockers (BB) are a mainstay of heart failure (HF) treatment, yet there are inconclusive data regarding their efficacy in African American individuals. METHODS AND
RESULTS: We performed a retrospective study of insured patients who received care from a large health system who were hospitalized for HF between January 2000 and June 2008 and had a documented ejection fraction <50%. BB exposure was estimated over 6-month rolling windows, using pharmacy claims data. Proportional hazards regression was used to test the association between BB exposure and all-cause hospitalization or death with adjustment for baseline covariates and other HF medication exposure. We performed analyses stratified by race and overall with a BB exposure×race interaction term. A total of 1094 patients met inclusion criteria (476 white and 618 African American individuals). Median follow-up was 2.1 years. In adjusted models, BB exposure was associated with lower risk of death or hospitalization in both groups, but more so in white individuals (hazard ratio, 0.40; 95% confidence interval, 0.27, 0.60; P<0.001) compared with African American individuals (hazard ratio, 0.67; 95% confidence interval, 0.48, 0.94; P=0.024). A formal test for interaction indicated that the protection association for BB exposure differed by race (P=0.098, β=0.40). Reanalysis restricted to BBs approved for HF or HF-specific hospitalizations did not substantively alter the findings.
CONCLUSIONS: BB appears to be 40-50% less effective in preventing death or hospitalization among African American patients with HF as compared with white individuals. Further study is needed to better understand BB effectiveness in African Americans with HF.