Differences in in-hospital mortality after STEMI versus NSTEMI by sex. Eleven-year trend in the Spanish National Health Service

Abstract

Introduction and objectivesConflicting results have been reported on the possible existence of sex differences in mortality after myocardial infarction (MI). There is also a scarcity of data on the impact of sex on outcomes after ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). The aim of this study was to analyze sex difference trends in sex-related differences in mortality for STEMI and NSTEMI. MethodsA retrospective analysis of 445 145 episodes of MI (2005-2015) was carried out using information from the Spanish National Health System. The incidence rates were expressed as events per 10 000 person-years. The denominators (age-specific groups) were obtained from the nationwide census. We calculated crude and adjusted (multilevel logistic regression) mortality. Poisson regression analysis was used to study temporal trends for in-hospital mortality. ResultsA total of 69.8% episodes occurred in men. The mean age in men was 66.1±13.3 years, which was significantly younger than in women, 74.9±12.1 (P<.001). A total of 272 407 (61.2%) episodes were STEMI, and 172 738 (38.8%) were NSTEMI. Women accounted for 28.8% of STEMI and 33.9% of NSTEMI episodes (P <.001). The effect of female sex on risk-adjusted models for in-hospital mortality was the opposite in STEMI (OR for women, 1.18; 95%CI, 1.14-1.22; P <.001) and NSTEMI (OR for women, 0.85; 95%CI, 0.81-0.89; P <.001). MI hospitalization rates were higher in men than in women for all age groups [20 vs 7.7 per 10 000 individuals aged 35-94 years (P <.001)], with a trend to diminish in both sexes. ConclusionsWomen had a slight but significantly increased risk of in-hospital mortality after MI, but the effect of sex depended on MI type, with women exhibiting higher mortality for STEMI and lower mortality for NSTEMI