New research published in PLOS One this October reports not only do more women statistically die of acute myocardial infarction (AMI) than men, but they see dramatically increased mortality in the first year after their heart attack.

Corresponding author Georg Schmidt, MD, and colleagues in Germany and England wrote in the recently published study that while survivors of AMI are an increased risk of mortality due to re-infarction, arrhythmic events, heart failure and more, no studies have identified why women have consistently higher related death rates than men. In the past, Schmidt and co-authors wrote, these gaps in survival rates have been attributed to differences in age, comorbidities, symptom presentation and pathophysiology between men and women suffering similar attacks.

“Nevertheless, no solid data exist on the impact of these common sex differences on the post-AMI survival,” the authors wrote. “In particular, data on the importance of the common sex differences are missing in patients treated according to contemporary standards including acute coronary interventions and guideline-based acute pharmacologic treatment.”

Schmidt and his team used data from the ISAR-RISK and ART studies, which were conducted between 1996 and 2005 using patients who had suffered an AMI a month prior to enrollment, to match 802 women and 802 men who had experienced similar outcomes. Sexes were matched based on age, previous AMI history, sinus-rhythm presence, hypertension, diabetes mellitus, smoking status, left ventricular ejection fraction (LVEF) and revascularization therapy, the researchers wrote.

Women recruited for the study tended to be older and suffered from hypertension and diabetes more often than men. The oldest, sickest female patients were excluded from the matched cohort group so Schmidt et al. could more plainly identify sex differences among other large gaps between genders.

In the whole study group, Schmidt and colleagues found females showed an increased mortality compared to men, with a hazard ratio of 1.54. In terms of long-term mortality, both men and women in the matched subgroups saw similar death rates. However, the team reported, women displayed a high mortality rate in the first year after AMI—one significantly higher than in men. These results can’t be explained by age, cardiovascular risk factors or modes of acute treatment, the authors said, and suggest a need to follow female patients more closely the year after their heart attack than is currently the clinical standard.

“In everyday life, women often face different expectations after a heart attack than men,” Schmidt said in a press release from the Technical University of Munich. “They are expected to start ‘functioning’ again sooner, which means that they are subject to bigger stresses. Our study shows that it is important to pay close attention to female patients, especially in the first year after the event.”