Women are undertreated and have worse clinical outcomes than men after acute myocardial infarction. It remains uncertain whether the sex disparities in treatments and outcomes persist in the contemporary era and whether they affect all age groups equally.

Using the National Inpatient Sample (NIS) registry, we evaluated 1,260,200 hospitalizations for ST-elevation myocardial infarction (STEMI) between 2010 and 2016, of which 32% were for women. The age-stratified sex differences in care measures and mortality were examined. Stepwise multivariable adjustment models, including baseline comorbidities, hospital characteristics, and reperfusion and revascularization therapies, were used to compare measures and outcomes between women and men across different age subgroups.

Overall, women with STEMI were older than men and had more comorbidities. Women were less likely to receive fibrinolytic therapy, percutaneous coronary intervention (PCI), and coronary artery bypass surgery across all age subgroups. Women with STEMI overall experienced higher unadjusted in-hospital mortality (11.1% vs 6.8%; adjusted odds ratio [OR] = 1.039, 95% confidence interval [CI]: 1.003-1.077), which persisted after multivariable adjustments. However, when stratified by age, the difference in mortality became non-significant in most age groups after stepwise multivariable adjustment, except among the youngest patients 19-49 years of age with STEMI (women vs men: 3.9% vs 2.6%; adjusted odds ratio = 1.259, 95% confidence interval: 1.083-1.464).

Women with STEMI were less likely to receive reperfusion and revascularization therapies and had higher in-hospital mortality and complications compared with men. Younger women with STEMI (19-49 years of age) experienced higher in-hospital mortality that persisted after multivariable adjustment.