Comparative Efficacy of Transfusion Strategies in Women and Men With Myocardial Infarction and Anemia: Prespecified Secondary Findings From the MINT Trial

BACKGROUND: The optimal transfusion strategy in patients with acute myocardial infarction (AMI) and anemia may be influenced by sex differences in pathophysiology and cardiovascular outcomes. The Myocardial Ischemia and Transfusion trial (MINT) randomized patients with AMI and anemia to restrictive or liberal transfusion thresholds, but sex-stratified outcomes remain undefined. The objective was to evaluate whether the clinical effect of restrictive versus liberal red blood cell transfusion strategies differs by sex in patients hospitalized with AMI and anemia. METHODS: In this prespecified secondary analysis of the MINT trial, we examined outcomes by sex and transfusion strategy. The primary outcome was 30-day composite death or MI. Secondary outcomes included heart failure, stroke, cardiac death, and 180-day mortality. Adjusted relative risks (RRs) and hazard ratios (HRs) were estimated accounting for sex differences at baseline. Interactions between sex and transfusion effects were assessed. RESULTS: There were 3504 study participants, of whom 1593 (45.4%) were women. Women received fewer transfusions on average. Primary outcome occurred in 15.7% of women and 15.7% of men and occurred in 16.5% of women and 17.1% of men in the restrictive arm, versus 14.9% and 14.2% in the liberal arm, respectively. Women had a lower mortality between 30 and 180 days (11.0% versus 13.5%; P =0.04). There were no statistically significant interactions between sex and transfusion strategy for the primary outcome (interaction P =0.60). For 30-day cardiac death, a higher RR in men was observed in the restrictive transfusion arm (RR, 2.34; 95% CI, 1.48–3.70; interaction P =0.05). CONCLUSIONS: For MINT patients with anemia and AMI, women comprised nearly half of the study population, and randomization to a restrictive or liberal transfusion strategy resulted in comparable outcomes in women and men. These findings support sex-neutral transfusion thresholds. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02981407.