LAUSR

AIMS There are sex differences in presentation, treatment, and outcomes of myocardial infarction (MI) but less is known about these differences in a younger patient population. The objective of this study was to investigate sex differences among individuals who experience their first MI at a young age. METHODS AND RESULTS Consecutive patients presenting to two large academic medical centres with a Type 1 MI at ≤50 years of age between 2000 and 2016 were included. Cause of death was adjudicated using electronic health records and death certificates. In total, 2097 individuals (404 female, 19%) had an MI (mean age 44 ± 5.1 years, 73% white). Risk factor profiles were similar between men and women, although women were more likely to have diabetes (23.7% vs. 18.9%, P = 0.028). Women were less likely to undergo invasive coronary angiography (93.5% vs. 96.7%, P = 0.003) and coronary revascularization (82.1% vs. 92.6%, P < 0.001). Women were significantly more likely to have MI with non-obstructive coronary disease on angiography (10.2% vs. 4.2%, P < 0.001). They were less likely to be discharged with aspirin (92.2% vs. 95.0%, P = 0.027), beta-blockers (86.6% vs. 90.3%, P = 0.033), angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers (53.4% vs. 63.7%, P < 0.001), and statins (82.4% vs. 88.4%, P < 0.001). There was no significant difference in in-hospital mortality; however, women who survived to hospital discharge experienced a higher all-cause mortality rate (adjusted HR = 1.63, P = 0.01; median follow-up 11.2 years) with no significant difference in cardiovascular mortality (adjusted HR = 1.14, P = 0.61). CONCLUSIONS Women who experienced their first MI under the age of 50 were less likely to undergo coronary revascularization or be treated with guideline-directed medical therapies. Women who survived hospitalization experienced similar cardiovascular mortality with significantly higher all-cause mortality than men. A better understanding of the mechanisms underlying these differences is warranted.