Sex Difference in the Case Fatality of Older Myocardial Infarction Patients

The female sex is associated with poorer outcomes after myocardial infarction (MI), although current evidence in older patients is limited and mixed. We sought to evaluate sex-based differences in outcome after MI in older patients.

Consecutive older (≥70 years) all-comer patients with out-of-hospital MI admitted to 20 hospitals in Finland between 2005 and 2014 were studied using national registries (n = 40 654, mean age 80 years, 50% women). The outcome of interest was death within 1 year after MI. Differences between sexes (age, baseline features, medication, comorbidities, revascularization, and treating hospital) were balanced by inverse probability weighting.

Adjusted all-cause case fatality was lower in women than in men at 30 days (16.0% vs 19.0%, respectively) and at 1 year (27.7% vs 32.4%, respectively) after MI (hazard ratio: 0.83; confidence interval [CI]: 0.80-0.86; p < .0001). Excess 1-year case fatality after MI compared to the corresponding general population was 22.1% (CI: 21.4%-22.8%) in women and 24.1% (CI: 23.4%-24.9%) in men. Women had a lower adjusted hazard of death after MI in subgroups of patients aged 70-79 years and ≥80 years, patients with and without ST elevation MI, revascularized and non-revascularized patients, patients with and without atrial fibrillation, and patients with and without diabetes. The sex difference in case fatality remained similar during the study period.

Older women were found to have a lower hazard of death after an out-of-hospital MI when compared to older men with similar features and treatments. This finding was consistent in several subgroups.