Impact of Adherence to Beta-Blockers in All-Comers ST-segment Elevation Myocardial Infarction (STEMI) Patients and According to Left Ventricular Ejection Fraction (LVEF) at Discharge: Results from the Real-World Registry FAST-STEMI.

Beta-blockers are a crucial part of post-myocardial infarction (MI) pharmacological therapy. Recent studies have raised questions about their efficacy in patients without reduced left ventricular ejection fraction (LVEF). This study aims to assess adherence to beta-blockers after discharge for ST-segment elevation myocardial infarction (STEMI) and the impact of adherence on outcomes based on LVEF at discharge. The retrospective registry FAST-STEMI evaluated real-world adherence to main cardiovascular drugs in STEMI patients between 2012 and 2017 by comparing purchased tablets to expected ones at one year through pharmacy registries. Optimal adherence was defined ≥80%. Primary outcomes included all-cause and cardiovascular death, while secondary outcomes were myocardial infarction, major/minor bleeding events, and ischemic stroke The study included 4688 patients discharged on beta-blockers. Mean age was 64 ± 12.3 years, 76% were male, and mean LVEF was 49.2 ± 8.8%. Mean adherence at one year was 87.1%. Optimal adherence was associated with lower all-cause (adjHR 0.62, 95%CI 0.41-0.92, p 0.02) and cardiovascular mortality (adjHR 0.55, 95%CI 0.26-0.98, p 0.043). In LVEF ≤40% patients, optimal adherence was linked to reduced all-cause and cardiovascular mortality but this was not found either in patients with preserved or mildly reduced LVEF. Predictors of cardiovascular mortality included older age, chronic kidney disease, male gender, and atrial fibrillation. Optimal adherence to beta-blocker therapy in all-comers STEMI patients reduced all-cause and cardiovascular mortality at 1 year; once stratified by LVEF, this effect is confirmed only in patients with reduced LVEF (< 40%) at hospital discharge.