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

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.