Introduction: The utilization of cardiac rehabilitation (CR) among patients, who experience a myocardial infarction (MI) at a young age, and its prognostic implications have not been well studied. We investigated the prevalence of and factors related to the use of CR in young individuals who presented with a first MI.
Methods: We conducted a retrospective cohort study of patients admitted with their first MI at a young age (≤ 50 years) at two tertiary care hospitals between January 2000 and April 2017, excluding those who died within 30 days of MI. Participation in CR and factors associated with participation were captured from electronic medical records and review of all clinic notes up to 1 year post- MI. Patients were followed over 1 year for a composite outcome of all-cause death, MI, coronary revascularization, or hospitalization for a cardiac cause. We estimated a propensity score for participation in CR, including: baseline characteristics, substance abuse, size of infarct, interventions, and medications at discharge. Cox proportional hazards modeling was performed to evaluate the association of CR participation on the composite outcome while adjusting for the propensity score.
Results: The cohort consisted of 1287 patients (mean age 44; 276 (21%) women; 688 (53%) STEMI), of which 206 (16%) participated in CR. Over 1 year of follow up 454 (35%) had a composite outcome. Individuals that underwent CR had better 1-year outcomes (unadjusted HR=0.69, [95% CI 0.53 to 0.91], p=0.008), which attenuated but remained statistically significant after adjustment for the propensity score (adjusted HR=0.72, [95% CI 0.54 to 0.94], p=0.018). This was mainly due to a significant reduction in readmissions for a cardiac cause.
Conclusion: Despite markedly low rates, cardiac rehabilitation participation is associated with significantly improved 1-year outcomes in young MI survivors.