Beta-Blockers: Useless vs Heart Attacks & Worse For Women?

Currently, more than 80% of uncomplicated heart attack patients are discharged on beta-blockers—this has been the go-to standard of care for the past 40 years—notwithstanding that there are common side effects such as bradycardia (slow heart rate), and resultant fatigue and sexual dysfunction.

However, researchers (Dr. Borja Ibanez et al.) have turned that on its head with a sweeping study involving 8,505 patients enrolled across 109 hospitals in Spain and Italy, randomized to receive or not receive beta-blockers, with a median follow-up of a little under 4 years.

What they found

In few words: overall, there was no significant differences between groups in death, recurrent heart attack, or hospitalization for heart failure.

However, for women specifically, they did find that there was (in the beta-blocker group), a slightly higher absolute risk of death over 3.7 years, plus higher rates of heart attack or heart failure hospitalization—specifically, they more often had heart attacks without obstructive coronary arteries.

Some of this disparity may be explained by the fact that women were less often prescribed recommended secondary prevention therapies (e.g. antiplatelet therapies, ACE inhibitors/ARBs, and cardiac rehabilitation) despite high overall prescription rates, but not all of it, because those receiving higher beta-blocker doses also saw a correspondingly higher risk.

You can find the paper itself here: Beta-Blockers after Myocardial Infarction without Reduced Ejection Fraction

And further modelling of more or less the same data here: Beta-blockers after myocardial infarction: effects according to sex in the REBOOT trial

You may be wondering: why “more or else”? Because they are both running numbers from the same trial, but the latter used only the intention-to-treat population, which was 8,438 out of the 8,505 patients.

One more thing…

While beta-blockers are generally considered “calming” (indeed, historically they’ve sometimes been prescribed for anxiety; less so nowadays), hence the bradycardia we mentioned in the introduction, this does mean that they can also promote depression—without actually alleviating anxiety:

❝At baseline, 27% of patients were possible cases of anxiety (m, 5.6; SD, 3.9) and 14% were possible cases of depression (m, 3.9; SD, 3.2). Beta-blocker treatment had a [worsening] effect on depressive symptoms at both follow-ups 1 (β = 0.48; 95% CI 09–0.86; P = 0.015) and 2 (β = 0.41; 95% CI = 0.01–0.81; P = 0.047), but no effect on anxiety.❞

Read in full: Short- and long-term effects of beta-blockers on symptoms of anxiety and depression in patients with myocardial infarction and preserved left ventricular function: a pre-specified quality of life sub-study from the REDUCE-AMI trial

Want to learn more?

For more on sex differences in this matter, see:

• Statins: His & Hers ← for women, statins are (in most cases) less useful and more potentially harmful
• Heart Attacks: His & Hers

And for why a lot of this kind of medical disparity occurs when it comes to outcomes:

Unwell Women: Misdiagnosis and Myth in a Man-Made World – by Elinor Cleghorn

Take care!