[Sex differences in incidence of mortality after acute myocardial infarction]

Abstract

Background: Previous studies have indicated that the mortality after acute myocardial infarction (AMI) is higher among women than among men. However, whether this difference is attributable to the older age of the women studied or to the presence of other unfavorable prognostic factors remains unclear.

Methods: This retrospective study compares the clinical features, management and 30-day outcome in men and women from a consecutive, unselected series of 878 patients with AMI (225 women, 25.7%) who were admitted to the coronary care unit. The studied variables included demographic, history and risk factors, the ECG at the time of admission and treatment assignment. The analysis, both unadjusted as well as adjusted, was performed using multiple logistic regression.

Results: The overall mortality rate during hospitalization was 24.4% for women and 13.2% for men (p < 0.0001). Women were, on average, significantly older than men (71.6 vs 62.3 years, p < 0.0001), had a higher prevalence of hypertension (58.2 vs 41.5%, p < 0.0001) and diabetes mellitus (33.7 vs 19.6%, p < 0.0001), were less frequently smokers (22.2 vs 52.3%, p < 0.0001) and waited longer resorting to the coronary care unit following the onset of symptoms (p < 0.005). Thrombolytic therapy was prescribed less often in women (19.1 vs 40.7%, p < 0.0001). Women had more mechanical complications than men (acute pulmonary edema, p < 0.0001; cardiogenic shock, p < 0.03). No significant difference was found between sexes regarding previous coronary events, the size and type of infarction, the ECG at the time of admission and arrhythmic or ischemic complications. After adjustment, female gender was not an independent predictor of mortality, following AMI. Mortality rates after AMI remained significantly higher for women than for men only among patients who had not received thrombolysis (odds ratio 1.90, 95% confidence interval 1.08-3.34, p < 0.03).

Conclusions: Much of the increased post-AMI mortality observed in women could be attributed to age, risk factors, comorbidity and other baseline characteristics. Female gender seems to be independently associated with a higher risk of death after AMI only among patients to whom thrombolytic therapy is not prescribed.