A new large-scale epidemiological study shows that mortality from heart attacks (myocardial infarctions) among adult patients under 55 in the United States increased between 2011 and 2022, with the rise being particularly pronounced among women, according to the American Heart Association.

The analysis covered nearly 1 million hospitalizations for first acute myocardial infarction, including both the more severe form with ST-segment elevation (STEMI) and the less severe non-ST-segment elevation type (NSTEMI), and identified a steady increase in in-hospital deaths.

In the overall group of adults under 55, the mortality rate after a first severe heart attack increased by 1.2 percentage points during the study period — a change researchers described as alarming, since it had previously been believed that declining mortality from cardiac events applied across all age groups. The earlier positive trend in the early 2010s appears to have been driven mainly by older adults and men.

A key and particularly striking finding was that women under 55 had higher in-hospital mortality after a first heart attack compared to men of the same age, both for the more severe STEMI (approximately 3.1% among women versus 2.6% among men) and for the less severe NSTEMI (about 1% versus less than 1%). Complication rates during hospitalization were roughly similar between women and men, but women were less likely to receive cardiovascular procedures to determine the cause and treat the heart attack.

Researchers also noted that younger women more frequently had nontraditional risk factors — such as low income, kidney disease, or use of certain drugs — which were more strongly associated with fatal outcomes in the analysis than classic risk factors (such as high blood pressure or elevated cholesterol).

After adjusting for all studied factors, these associations remained significant.

The authors emphasize that the rise in mortality among younger adults, especially women, underscores the need for earlier identification of cardiovascular risks, greater attention to nontraditional risk factors, and adaptation of diagnostic and treatment approaches for heart attacks in this age group.