Outcomes in the BETAMI-DANBLOCK trial compared with a Norwegian nationwide myocardial infarction population.

Abstract (English)

BACKGROUND AND AIMS: In patients with myocardial infarction (MI), no heart failure, and left ventricular ejection fraction (LVEF) ≥ 40%, the combined BETAMI-DANBLOCK trial showed that beta-blockers reduced the risk of all-cause mortality or major adverse cardiovascular events. This study evaluated the representativeness of the trial. METHODS: Participants in BETAMI (n = 2867) and DANBLOCK (n = 2707) were compared with a cohort of revascularized MI patients with LVEF ≥40%, and no heart failure from the Norwegian Myocardial Infarction Registry (the NORMI cohort)(n = 20 804). Baseline characteristics were evaluated, and absolute risks of all-cause mortality and/or MI were estimated. A transportability analysis was conducted by weighting the BETAMI-DANBLOCK population according to the NORMI cohort. RESULTS: Median age was 66 years (interquartile range [IQR]: 57-74) in the NORMI cohort and 63 years (IQR: 55-70) in BETAMI and DANBLOCK. Patients in the NORMI cohort had a higher prevalence of diabetes, previous coronary artery disease, and LVEF 40-49%, compared with trial participants. At 3-year follow-up, the absolute risk of all-cause mortality or MI was 12.0% in the NORMI cohort, 7.7% in BETAMI, and 7.8% in DANBLOCK. Corresponding risks of MI were 6.3%, 5.6%, and 4.3%, respectively. The treatment effects of beta-blockers were similar when the trial population was weighted according to the characteristics of the NORMI cohort. CONCLUSIONS: Compared with the NORMI cohort, participants in BETAMI and DANBLOCK were younger, had a lower proportion of certain comorbidities, and experienced a lower risk of all-cause mortality and MI. Despite these differences, the effect of beta-blockers remained consistent when the trial population was weighted according to the NORMI cohort.