Sex differences in 1-year all-cause rehospitalization in patients after acute myocardial infarction: a prospective observational study

Abstract

Background: Compared with men, women are at higher risk of rehospitalization in the first month after discharge for acute myocardial infarction (AMI). However, it is unknown whether this risk extends to the full year and varies by age. Explanatory factors potentially mediating the relationship between sex and rehospitalization remain unexplored and are needed to reduce readmissions. The aim of this study was to assess sex differences and factors associated with 1-year rehospitalization rates after AMI. Methods: We recruited 3536 patients (33% women) ≥18 years of age hospitalized with AMI from 24 US centers into the TRIUMPH study (Translational Research Investigating Underlying Disparities in Acute Myocardial Infarction Patients' Health Status). Data were obtained by medical record abstraction and patient interviews, and a physician panel adjudicated hospitalizations within the first year after AMI. We compared sex differences in rehospitalization using a Cox proportional hazards model, following sequential adjustment for covariates and testing for an age-sex interaction. Results: One-year crude all-cause rehospitalization rates for women were significantly higher than men after AMI (hazard ratio, 1.29 for women; 95% confidence interval, 1.12-1.48). After adjustment for demographics and clinical factors, women had a persistent 26% higher risk of rehospitalization (hazard ratio, 1.26; 95% confidence interval, 1.08-1.47). However, after adjustment for health status and psychosocial factors (hazard ratio, 1.14; 95% confidence interval, 0.96-1.35), the association was attenuated. No significant age-sex interaction was found for 1-year rehospitalization, suggesting that the increased risk applied to both older and younger women. Conclusions: Regardless of age, women have a higher risk of rehospitalization compared with men over the first year after AMI. Although the increased risk persisted after adjustment for clinical factors, the poorer health and psychosocial state of women attenuated the difference.