Paradoxical lower postmyocardial infarction mortality among veteran women--does a sex bias exist in the Veterans Affairs medical system?

backgroundOutcomes after acute coronary disease are reportedly worse among women in general and more so among women with diabetes compared with men. Sex differences were evaluated in postmyocardial infarction (MI) mortality among veterans (who are predominantly male) to determine whether evaluation and treatment in Veterans Affairs hospitals amplifies sex differences in outcome.

methodsAll patients discharged with the primary diagnosis of acute MI from any Veterans hospitals in the United States between October 1990 and September 1997 were identified. Demographic, comorbidity, inpatient, outpatient, mortality and readmission data were extracted. Mortality, revascularization and readmissions were compared between male and female patients using Cox regression models.

resultsThe authors identified 67,889 patients with MI, 17,756 (26%) of whom had diabetes. There were 951 women, 280 (29%) of whom had diabetes, and 66,938 men, 17,476 (26%) of whom had diabetes. Over the entire follow-up period, adjusted mortality was higher in men than women (hazard ratio [HR] 1.5, 95% CI 1.3 to 1.7). Cardiac procedures were significantly higher among men: HR for coronary bypass surgery was 2.1 (95% CI 1.6 to 2.8; P<0.001) for all men, while HR for catheterization and percutaneous coronary intervention were higher for men among nondiabetics only--1.5 (95% CI 1.2 to 1.8; P<0.001) and 2.0 (95% CI 1.4 to 2.9; P<0.001). Interaction between sex and diabetes was not significant.

conclusionsContrary to previous observations in the nonveteran population, long-term mortality post-MI was lower among veteran women, despite higher procedure rates in men. The present study also failed to show increased mortality in women with diabetes.