A pooled data analysis of 11 randomized controlled trials has found that β blockers reduce the risk of death and hospitalization in patients with reduced ejection fraction (HFrEF) and sinus rhythm, regardless of age or sex. The research team – consisting of researchers from Europe, Australia, USA, and Canada – analyzed trials that reported mortality as a primary outcome or part of a composite outcome comparing β blockers to placebo.
The 11 trials contained 18,637 patients who matched the criteria for inclusion. The final population size for the fully adjusted Cox model for the primary outcome was 13,670. The median age was 64, 24% were women (n=3,283) and were older than men (66 [58-73] vs. 63 [55-71]).
Analyses showed a significant reduction in all cause mortality with β blockers compared to placebo (13.7% vs.18.0%, respectively). This transferred to a relative risk reduction of 24% with β blockers, with an absolute risk reduction of 4.3%. The adjusted hazard ratio was 0.70 (95% confidence interval 0.64 to 0.77); P<0.001).
The secondary outcome was admission to hospital for heart failure, for this the authors noted a slight lessening of the benefits of β blockers as patients got older. For the youngest quarter (median age 50) the percentage of all ≥1 admissions was 39% for women and 31% for men. For the second age quarter (median age 60) it was 35% for women and 36% for men; the third age quarter (median age 68) was 39% for women and 40% for men, and the fourth age quarter (median age 75) was 40% for women and 43% for men. However these figures still represent a significant reduction of events, even in the oldest group.
Between the sexes women demonstrated a lower incidence of ischemic etiology and previous myocardial infarct, but had a similar prevalence of heart failure compared to men. Women were shown to have a better prognosis than men but mortality rates were still at 25% over 3 years.
The authors asserted that their findings demonstrate the efficacy of β blockers in reducing all cause mortality, with the reductions being similar across age quarters with no significant interaction when an adjusted continuous hazard model was used.
With the tolerability of β blockers similar to placebo, they concluded that these findings should discourage the practice of withholding this treatment from women or the elderly.
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