Effect on Mortality of Higher Versus Lower ß-Blocker (Metoprolol Succinate or Carvedilol) Dose in Patients With Heart Failure.

This study aimed to compare the effect of ß-blocker dose and heart rate (HR) on mortality in patients with heart failure with reduced ejection fraction (HFrEF). The Veteran Affairs databases were queried to identify all patients diagnosed with HFrEF based on International Classification of Diseases Ninth Revision codes from 2007 to 2015 and ß-blocker (carvedilol or metoprolol succinate) use. 36,168 patients on low dose ß blocker were then matched with 36,168 patients on high dose ß-blocker using propensity score matching. The impact of ß-blocker dose and HR was assessed on overall mortality using Cox proportional hazard model. After dividing average HR into separate quartiles and adjusting for patient characteristics, high ß-blocker dose was associated with lower overall mortality as compared with a low dose of ß blocker (hazard ratio 0.75, 95% confidence interval 0.73 to 0.77, p <0.01) independent of the HR achieved. The results held for all 4 quartiles of average HR. A higher ß-blocker dose or a lower HR were independently and jointly associated with lower mortality for all quartiles of HR. In conclusion, higher dose of ß-blocker therapy and a lower achieved HR were independently associated with a reduction in mortality in HFrEF patients.