Beta-blocker therapy beyond 1 year after MI fails to improve survival
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Beta-blocker therapy did not improve survival beyond 1 year after an MI, although a dose-dependent effect was observed, according to findings from a landmark analysis of the OBTAIN registry.
“This analysis suggests that patients treated with greater than 12.5% to 25% of the target dose used in prior randomized clinical trials beyond 1 year after MI may have enhanced survival compared with no beta-blocker and other beta-blocker doses,” Jeffrey J. Goldberger, MD, MBA, of the University of Miami Miller School of Medicine, and colleagues wrote.
Despite beta-blockers currently being recommended after an MI, the benefits of long-term therapy have not been established, Goldberger and colleagues noted in the study. This led them to assess beta-blocker efficacy by dose in MI survivors at 1 year.
In all, the OBTAIN registry included 7,057 patients with acute MI and 6,077 1-year survivors. Researchers reported beta-blocker dose status availability in 3,004 patients, which was analyzed by use (binary) and dose at 1 year after MI. They used the following target doses from randomized clinical trials as classification: no beta-blocker; greater than 0% to 12.5%; greater than 12.5% to 25%; greater than 25% to 50%; and greater than 50%.
Mean patient age was consistently 63 to 64 years across groups; roughly two-thirds of patients were men; and median follow-up was 1.05 years.
In dichotomous analysis, beta-blocker therapy failed to improve survival. Propensity score analysis by dose revealed a significant increase in mortality in the following groups when compared with those in the greater than 12.5% to 25% dose group:
- no beta-blocker: HR = 1.997; 95% CI, 1.118-3.568; P < .02;
- greater than 0% to 12.5%: HR = 1.817; 95% CI, 1.094-3.016; P < .02; and
- greater than 25% to 50%: HR = 1.764; 95% CI, 1.105-2.815; P < .02.
The difference in mortality in the full-dose group did not reach statistical significance (HR = 1.196; 95% CI, 0.687-2.083). Subgroup analyses revealed only history of congestive HF to have a significant interaction with the effect of beta-blockers on survival.
The researchers wrote that given the tremendous advances made in the management of acute MI and post-MI treatments, it is necessary to reconsider the role of beta-blocker therapy.
“However, the relevant question is no longer whether all patients with acute MI should be treated with beta-blockers,” they wrote. “The OBTAIN study and this substudy support the need for a new paradigm that addresses which patients should be treated, for how long, and at what dose. An important role for personalized medicine in the management of this diverse patient population must be incorporated. Further randomized clinical trials are required to prospectively test dosing and treatment durations for beta-blocker therapy following acute MI.”
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