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Beta-blockers may not benefit some patients with MI
Among patients with acute MI who did not have HF, the use of beta-blockers did not lower the risk for death at 1 year after MI, according to published findings.
“Historically, beta-blockers have been the standard of care for patients with acute MI. However, clinical uncertainty exists regarding their effectiveness in reducing mortality among patients with [acute] MI who do not have HF or left ventricular systolic dysfunction (LVSD),” Tatendashe B. Dondo, MSc, of the Medical Research Council Bioinformatics Centre, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom, and colleagues wrote. “For example, although there is sufficient evidence to support the use of beta-blockers in patients with [acute] MI and HF, as well as in hospitalized patients who are hemodynamically stable, there are no contemporary randomized data for survivors of [acute] MI without HF or LVSD in relation to the use of beta-blockers.”
Beta-blocker usage
Dondo and colleagues used data from a U.K. national registry for MI to identify survivors of hospitalization for acute MI without HF or LVSD (n = 179,810; 91,895 with STEMI; 87,915 with non-STEMI) between 2007 and June 2013. Beta-blocker usage was defined as participants receiving the drug at hospital discharge.
Of participants with STEMI, 96.4% received beta-blockers compared with 93.2% of participants with non-STEMI. Those who received beta-blockers were more likely to be younger, to be men and to have more comorbidities.
During 1 year of follow-up, 5.2% (n = 9,373) of participants died. Unadjusted 1-year mortality was lower in participants who received beta-blockers (4.9%) vs. those who did not (11.2%; P <.001).
In a propensity score analysis after weighting and adjustment, there was no significant difference in mortality in those prescribed beta-blockers vs. those who were not (average treatment effect coefficient = 0.07; 95% CI, –0.6 to 0.75). This was true for both the STEMI cohort and the non-STEMI cohort.
“This was an observational study based on robust statistical analysis of large-scale patient data,” Marlous Hall, PhD, of the Medical Research Council Bioinformatics Centre, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, United Kingdom, said in a press release. “What we need now is a randomized patient trial. We were investigating one outcome — did beta-blockers increase a patient’s changes of survival? A trial would allow researchers to substantiate these findings and also look at other outcomes, such as whether beta-blockers prevent future [MIs]. This work would have implications for personalizing medications after [an MI].”
H ypothesis-generating
In an accompanying editorial, Borja Ibáñez, MD, of the Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, and colleagues wrote that a retrospective, observational study has limitations. They also expressed concern that the LV ejection fraction used to define systolic dysfunction was 30%.
“Even in the absence of randomized controlled trials, results from these kinds of studies should be seen with extreme caution, as they may not necessarily provide reliable answers on how to best treat patients,” they wrote. “Thus, as the authors acknowledge, the present study should be viewed as hypothesis-generating and should not change clinical practice. However, this important report highlights the need to reboot the system: the role of beta-blockers in post-MI patients without LVSD (LVEF > 40%) needs to be evaluated from scratch.” – by Cassie Homer
Disclosure: Dondo and Hall report receiving funding from the British Heart Foundation. Please see the full study for a list of the other researchers’ relevant financial disclosures. Ibáñez and colleagues report no relevant financial disclosures.