Women with AMI have higher CV death compared with men and may benefit from better adherence to guidelines
Sex Differences in Treatments, Relative Survival, and Excess Mortality Following Acute Myocardial Infarction: National Cohort Study Using the SWEDEHEART Registry
Although several studies showed that following an acute myocardial infarction (AMI), gender is no longer an independent predictor of death after adjustment for age and comorbidities, there are still differences in the estimates of the impact of gender on post-MI survival. This is partly because women without AMI have a better underlying prognosis than men without AMI, and due to the use of all-cause mortality as the clinical outcome to report survival [1-4].
In this study, the impact of gender on relative survival and excess mortality following AMI was evaluated, in a population-based cohort within a relative survival framework. Moreover, factors associated with differences in survival were identified. 180,368 patients included in the SWEDEHEART registry , aged >18 years and hospitalized for AMI between 2003 and 2013, were eligible for the analysis. The primary outcome was excess mortality at 6 months, 1 year, and 5 years following hospitalization for AMI.
- For women, there were 30,202 (46.2%) deaths in 271,824 person-years at risk (PYAR), and for men 39,702 (34.5%) deaths in 540,771 PYAR.
- The median time to death was shorter for women compared with men (1.7 years; IR: 0.3–4.3 years vs 1.9 years; IR: 0.3–4.6 years; P<0.001).
- For STEMI, the all-cause mortality analysis showed no gender difference in mortality adjusted for age, year of hospitalization, and comorbidities at 6 months, 1 year, and 5 years. For NSTEMI, women had a small reduction in mortality compared with men at 6 months, 1 year, and 5 years.
- The estimated average relative survival adjusted for age and year was lower for women with STEMI than for men at 6 months (84.8% vs 87.6%), 1 year (83.2% vs 86.8%), and 5 years (75.1% vs 82.4%). For NSTEMI, the difference in relative survival between men and women was not evident at 6 months (90.0% vs 89.6%) and 1 year (86.9% vs 87.0%), but was lower in women than men at 5 years (73.1% vs 76.0%).
- Women with STEMI had a 2-fold increase in excess mortality after adjustment for age and year of hospital admission at 6 months (excess mortality rate ratios [EMRR]: 2.12 [95% CI, 1.85–2.42]), a 3-fold increase at 1 year (EMRR: 3.29 [95% CI, 2.40–4.51]), and an almost 2-fold increase at 5 years (EMRR: 1.91[ 95% CI),. For NSTEMI, the effects were smaller but significant at 6 months (EMRR: 1.14 [95% CI, 1.10–1.18]), 1 year (EMRR: 1.24 [95% CI, 1.19–1.29]), and 5 years (EMRR: 1.35 [95% CI, 1.28–1.42].
- After further adjustment for the use of guideline-indicated treatments, excess mortality among women with STEMI reduced excess mortality for women compared with men at 6 months (EMRR: 1.26 [95% CI, 1.16–1.37]), 1 year (EMRR: 1.43[ 95% CI, 1.26–1.62]), and 5 years (EMRR: 1.31 [95% CI, 1.19–1.43]. In NSTEMI, excess mortality was no longer significant after adjustment for treatments at 6 months (EMRR: 0.97 [95% CI, 0.94–1.00]) and 1 year (EMRR: 1.01 [95% CI, 0.97–1.04]), but remained significant at 5 years (EMRR: 1.07 [95% CI, 1.02–1.12]).
Women with AMI in Sweden had a higher excess mortality compared with men, which was reduced after adjustment for the use of guideline-indicated treatments. This finding suggests that improved adherence to guideline recommendations for the treatment of AMI may reduce premature CV death among women.