Sex-related Differences in Exercise Capacity Trends and Determinants after Cardiac Rehabilitation in Patients with Acute Myocardial Infarction.

Objective: This study aimed to investigate whether longitudinal changes in exercise capacity in patients with acute myocardial infarction (AMI) differ by sex and clarified what contributed to these differences.

Methods: We retrospectively examined the differences in each variable between men and women in 156 patients with AMI (mean age: 65 ± 12 years; 82.0% male) who participated in a 3-month cardiac rehabilitation (CR) program and could be followed-up for exercise capacity 12-months after AMI onset. Sex-related differences in the change in peak oxygen uptake (peak VO₂) at baseline, 3-months, and 12-months after AMI were analyzed.

Results: Male patients with AMI were younger and had higher body mass index and employment rate than women. The attendance of the CR program was higher in women (men vs. women; 10 [3-15] vs. 14 [11-24] sessions, p = 0.0002). Women showed a significant lower %change in peak VO₂ after 12 months (men vs. women; 7.8% [-0.49% to 14.6%] vs. 1.3% [-5.7% to 7.5%], p = 0.013). In multiple linear regression analysis, age (β = -0.76, 95% confidence interval [CI] = -1.0 to -0.50, p <0.0001) and female sex (β = -6.3, 95% CI = -9.1 to -3.5, p <0.0001) were negative independent predictors of change in peak VO₂ over 12 months, while CR attendance (β = 0.21, 95% CI = 0.0032-0.42, p = 0.047) and recommended exercise habit after the CR program (β = 2.1, 95% CI = 0.095-4.1, p = 0.040) were positive independent predictors of change in peak VO₂ over 12 months.

Conclusion: In female patients, exercise capacity improved during the CR program but decreased to AMI onset levels after 12 months.