In Beta-Blocker Evaluation of Survival Trial (BEST) bucindolol significantly reduced mortality among Caucasians with systolic heart failure (HF) but not among African Americans. Whether this differential effect can be explained by racial differences in baseline characteristics has not been previously examined. Of the 2708 BEST participants, 627 were African Americans. Because African Americans were more likely to be younger and women, we used age-sex-adjusted hazard ratios (HR) and 95% confidence intervals (CI) to estimate their outcomes (vs. Caucasians). A step-wise multivariable-adjusted model using 24 baseline characteristics was used to identify variables associated with between-race outcome differences and propensity-matching was used to determine independence of associations. Age-sex-adjusted HR for all-cause mortality for African Americans during 2 years of mean follow-up was 1.27. African Americans were more likely to have lower right ventricular ejection fraction. African Americans had no association with mortality among propensity-matched patients. The higher risk of death among African Americans in BEST may in part be due to their lower RVEF which may in part explain the lack of response to bucindolol among these patients. Future studies need to examine the role of low RVEF on the effect of beta-blockers in patients with systolic HF.
