Associations of Exercise Capacity After Myocardial Infarction with Mortality and Major Adverse Cardiovascular Events: Sex-Specific Findings from the Nationwide SWEDEHEART Cohort.

Aim

Investigate sex-specific associations between exercise capacity and the risk of all-cause mortality and major adverse cardiovascular events (MACE) after myocardial infarction (MI), using nationwide real-world data.

Methods

A prospective cohort study using the SWEDEHEART registry. Patients with an MI (2016-2020) were included. Exercise capacity (maximal workload in Watts) was assessed using bicycle ergometer testing performed before exercise-based cardiac rehabilitation, 2-8 weeks after hospital discharge. Outcomes were all-cause mortality and MACE (MI, stroke, and cardiovascular death), identified in national cause-of-death and patient registries (2016-2023). Associations between exercise capacity and outcomes were evaluated using adjusted Cox proportional hazard models. The functional form of the association was assessed using restricted cubic splines.

Results

There were 15,945 patients (78% men), with a median age of 64 (IQR: 56-70) years, included. During a median follow-up of 3.2 (2.3-4.3) years, 420 deaths and 948 MACE occurred. Higher exercise capacity (per 10-Watt increase) was associated with an 18% lower hazard of death in men and a 33% lower hazard in women, with a linear association for both sexes. Similarly, MACE hazard decreased by 8% in men and 18% in women per 10-Watt increase in exercise capacity, with a curvilinear association for men and linear association for women.

Conclusion

Higher exercise capacity measured by routine clinical exercise testing was associated with lower risk of all-cause mortality and recurrent MACE, with stronger associations in women. These findings support the use of exercise capacity testing to identify patients at the highest risk.