Less revascularization in young women but impaired long-term outcomes in young men after myocardial infarction

AIMS: Female sex has previously been associated with poorer outcomes after myocardial infarction (MI), although evidence is scarce among young patients. We studied sex differences in cardiovascular outcomes after MI in young patients <55 years old. METHODS AND RESULTS: Consecutive young (18-54 years) all-comer patients with out-of-hospital MI admitted to 20 Finnish hospitals (n = 8934, 17.3% women) in 2004-2014 were studied by synergizing national registries. Differences between the sexes were balanced by inverse probability weighting. The median follow-up period was 9.1 years (max 14.8 years). Young women with MI had more comorbidities at baseline, were revascularized less frequently, and received fewer evidence-based secondary prevention medications (P2Y12 inhibitors, renin-angiotensin signalling pathway inhibitors, statins, and lower statin dosages) after MI than young men. Long-term mortality or the occurrence of major adverse cardiovascular events (MACE; recurrent MI, stroke, or cardiovascular death) did not differ between the sexes in the unadjusted analysis. However, after baseline feature and treatment-difference adjustment, men had poorer outcomes after MI. Adjusted long-term mortality was 21.3% in men vs. 17.2% in women [hazard ratio (HR) 1.29; 95% confidence interval (CI) 1.10-1.53; P = 0.002]. Cumulative MACE rate was 33.9% in men vs. 27.9% in women during follow-up (HR 1.23; 95% CI 1.09-1.39; P = 0.001). Recurrent MI and cardiovascular death occurrences were more frequent among men. Stroke occurrence did not differ between the sexes. CONCLUSIONS: Young women were found to receive less active treatment after MI than young men. Nevertheless, male sex was associated with poorer long-term cardiovascular outcomes after MI in young patients after baseline feature adjustment.