Sex Differences in Outcomes After Myocardial Infarction in the Community

Prior studies observed that women experienced worse outcomes than men after myocardial infarction but did not convincingly establish an independent effect of female sex on outcomes, thus failing to impact clinical practice. Current data remain sparse and information on long-term nonfatal outcomes is lacking. To address these gaps in knowledge, we examined outcomes after incident myocardial infarction for women compared with men.

We studied a population-based myocardial infarction incidence cohort in Olmsted County, Minnesota, between 2000 and 2012. Patients were followed for recurrent myocardial infarction, heart failure, and death. A propensity score was constructed to balance the clinical characteristics between men and women; Cox models were weighted using inverse probabilities of the propensity scores.

Among 1959 patients with incident myocardial infarction (39% women; mean age 73.8 and 64.2 for women and men, respectively), 347 recurrent myocardial infarctions, 464 heart failure episodes, 836 deaths, and 367 cardiovascular deaths occurred over a mean follow-up of 6.5 years. Women experienced a higher occurrence of each adverse event (all P <0.01). After propensity score weighting, women had a 28% increased risk of recurrent myocardial infarction (hazard ratio: 1.28, 95% confidence interval: 1.03-1.59), and there was no difference in risk for any other outcomes (all P >0.05).

After myocardial infarction, women experience a large excess risk of recurrent myocardial infarction but not of heart failure or death independently of clinical characteristics. Future studies are needed to understand the mechanisms driving this association.