Sex Difference in Causes and Timing of One-Year Outcomes Among Young Acute Myocardial Infarction Patients; Results from the VIRGO Study

BackgroundYounger women have higher recurrent hospitalization rates and worse health status than men after their index episode of acute myocardial infarction (AMI). However, whether women have a higher risk of cardiovascular events in the year after discharge is unknown. MethodsWe used data from the VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients) study, which enrolled young AMI patients aged 18 to 55 years across 103 US hospitals. Sex differences in all-cause and cause-specific hospitalizations were compared by calculating incidence rates (IR, per 1,000 person-years) and incidence rate ratios (IRRs) with 95% confidence intervals (CIs). We then performed sequential modeling to evaluate the sex difference by calculating sub-distribution hazard ratios (SHR) accounting for deaths. ResultsAmong 2,007 women and 972 men, at least one all-cause hospitalization occurred among 905 (30.4%) participants in the year after discharge. The leading causes of hospitalization were MI-related (IR 171.8, 95% CI, 153.6-192.2 among women vs. IR 117.8, 95% CI, 97.3-142.6 among men), followed by non-cardiac (IR 145.8, 95% CI, 129.2-164.5 among women vs. IR 69.6, 95% CI, 54.5-88.9 among men) and other cardiac or stroke hospitalizations (IR 58.8, 95% CI, 48.8-70.7 among women vs. IR 53.8, 95% CI, 40.8-71.0 among men). Competing risk analysis showed that the sex difference was present for MI-related hospitalizations (SHR 1.33, 95%CI 1.04-1.70; P=0.02) and non-cardiac hospitalizations (SHR 1.51, 95%CI 1.13-2.07; P=0.01). ConclusionsYoung women with AMI have more adverse outcomes compared with men in the year after discharge. MI-related hospitalizations were the most common cause of hospitalizations, but non-cardiac hospitalizations showed the most significant sex disparity. Further studies to better understand the underlying mechanisms of non-cardiac hospitalizations are warranted.