Many patients stay on a beta-blocker indefinitely after a myocardial infarction simply because nobody stopped it. This pooled analysis of individual patient data from the ABYSS and SMART-DECISION randomised trials tested whether that habit is necessary. It included 6,238 stable patients more than six months past their infarction, with a left ventricular ejection fraction of 40% or above and no heart failure: 3,092 randomised to discontinuation and 3,146 to continuation. Median time since the infarction was 3.6 years; median follow-up was 3.0 years.
The primary composite of death, myocardial infarction, stroke or cardiovascular hospitalisation occurred in 17.2% of those who stopped and 15.9% of those who continued, hazard ratio 1.09 (95% CI 0.97 to 1.24), meeting noninferiority against a margin of 1.25. The key secondary endpoint — death, myocardial infarction or heart failure hospitalisation — was 6.5% versus 6.4%, hazard ratio 1.01 (95% CI 0.83 to 1.23), comfortably noninferior against its margin of 1.40. Results were consistent across ejection fraction.
The authors are unusually candid about the weakness: the primary composite was hospitalisation-heavy and varied between the two trials, so the numerically higher event rate in the discontinuation arm is hard to interpret. The cleaner endpoint — the one containing only hard outcomes — was flat.
The practical value here is for anyone running a general clinic. A patient on a beta-blocker with no angina, no arrhythmia, no hypertension needing it and a preserved ejection fraction is on a drug that is doing nothing for their prognosis but may be causing fatigue, bradycardia or erectile dysfunction. This is a deprescribing opportunity with randomised support, which is rare.
- Review beta-blocker indication in every patient more than six months past a myocardial infarction
- Stopping is supported only where ejection fraction is 40% or above, there is no heart failure, and no other indication exists
- Check for the other reasons first — angina, atrial fibrillation, rate control, hypertension, migraine, tremor — before stopping
- Taper rather than stopping abruptly, and review blood pressure and heart rate a few weeks later
- Ask about the symptoms the drug may be causing: fatigue, exercise intolerance, cold extremities, sexual dysfunction, low mood
The statistics, in plain English
Noninferiority margins do most of the work in this analysis, and they were generous: 1.25 for the primary endpoint means discontinuation could be up to 25% worse and still be declared noninferior. The primary confidence interval, 0.97 to 1.24, sits almost entirely above 1.0 — that is, the data lean towards continuation being slightly better, but cannot exclude equivalence. The key secondary result, 0.83 to 1.23 centred on 1.01, is the reassuring one because it contains only hard outcomes. When a composite includes hospitalisation, differences in local admission thresholds between countries can move the result without any biological effect at all.
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