Sex differences in 2-year mortality after hospital discharge for myocardial infarction

Background: An interaction between sex and age is thought to affect hospita l mortality after myocardial infarction; younger, but not older, women have been shown to have higher mortality rates than men. It is currently unknow n whether findings are similar after hospital discharge. Objective: To determine whether an interaction between sex and age affects a-year mortality after myocardial infarction. Design: Community-based prospective cohort study. Setting: 16 community hospitals serving the Worcester, Massachusetts, metro politan area. Patients: 6826 patients who survived hospitalization for acute myocardial i nfarction during ten 1-year periods between 1975 and 1995. Measurements: Mortality 2 years after hospital discharge. Results: The overall 2-year mortality rate was higher in women (28.9%) than in men (19.6%). When patients were examined by age group, however, only wo men younger than 60 years of age had a higher mortality rate than men of si milar age. The sex difference decreased with increasing age; among the olde st patients, women had a lower mortality rate than men (P = 0.009 for the i nteraction between sex and age). This relationship was not affected by adju stment for demographic characteristics and medical history, clinical charac teristics, and hospital and discharge treatments; the hazard of 2-year deat h for women compared with men increased 15.4% (95% Cl, 4.3% to 27.6%) for e very 10-year decrease in age. In absolute terms, after adjustment for demog raphic characteristics and medical history, among patients younger than 60 years of age women were at greater risk than men (risk difference, 1.8 perc entage points). At older ages, however, women were at lower risk than men. Conclusions: Younger, but not older, women who survive hospitalization for myocardial infarction have a higher long-term mortality rate than men. This provides additional evidence that younger women with myocardial infarction are at greater risk for death than men.