Sex differences in acute myocardial infarction: Is it only the age?

BACKGROUND: Several studies have shown that, after an acute myocardial infarction, women have worse prognosis than males. However, it is not clear if female sex is an independent predictor of mortality risk. Our aim was to analyse sex influence on the prognosis of these patients.

METHODS: Retrospective registry of patients with ST segment elevation myocardial infarction (STEMI) from January 2010 to April 2015.

RESULTS: From 1111 patients, 258 (23.2%) were women. Compared with men, they presented higher risk profiles with older age (70.1±14.4years vs. 62.3±13.4, P<0.001), more cardiovascular risk factors (except smoking), longer time from symptoms onset to hospital arrival (5.2±4.1h vs. 4.2±3.7), higher Killip classification (1.6±1.1 vs. 1.4±0.8), fewer complete revascularizations (175 [67.8%] vs. 662 [77.9%] in men) and higher in-hospital mortality (26 [10.1%] vs. 34 [4.0%]); all p values <0.003. At discharge, women less frequently received ACE inhibitors (189 [81.1%] vs. 702 [85.8%], p=0.045) and presented more major adverse events (death, bleeding, infection, myocardial infarction, stent thrombosis or heart failure) during the first month after discharge (10.5% vs. 4.5%, p<0.001) and higher long-term mortality (hazard ratio [HR] 1.6, 95% CI 1.1-2.2). After adjusting by age, most of the differences disappeared, and sex was not an independent factor of in-hospital (odds ratio 1.71, 95% CI 0.97-2.99) or long-term mortality (HR 1.0, 95% CI 0.7-1.5).

CONCLUSIONS: In patients with acute STEMI, the association of female sex with poor prognosis is mainly explained by age. Sex does not seem to be an independent prognostic factor.