Cardiac Rehabilitation Participation and Outcomes in the 3 Years After Acute Coronary Syndrome: Linked Data Study of the SNAPSHOT ACS Audit

PURPOSE: This study aimed to compare 3-year outcomes between survivors of acute coronary syndrome (ACS) who did and did not attend cardiac rehabilitation (CR) programs. METHODS: This follow-up study of the SNAPSHOT ACS audit included 1069 patients across Australia. Clinical data were linked to hospitalizations, mortality, and pharmacotherapy dispensing datasets for people hospitalized with ACS and analyzed in the 3 years following index admission. Outcomes were all-cause mortality and readmissions for myocardial infarction (MI), stroke, and heart failure. RESULTS: The cohort was aged 67 ± 13 years, 66% male, 57% had a discharge diagnosis of MI, and 36% attended CR. Attendees of CR were younger (65 ± 11 vs 69 ± 13 years, P < .001), more likely to be male (72% vs 63%, P = .002) and receive revascularization interventions (percutaneous coronary intervention: 48% vs 29%, P < .001; coronary artery bypass graft surgery: 14% vs 4.4%, P < .001), and less likely to have a history of MI (23% vs 30%, P = .014) than nonattendees. Compared with nonattendees, attendees of CR had a lower risk of all-cause mortality (HR = 0.53: 95% CI, 0.31-0.88) but a greater risk of MI readmissions (HR = 1.82: 95% CI, 1.28-2.59) over 3-year follow-up. There was no significant difference in the hazard of stroke and heart failure between attendees and nonattendees. The prescription of ≥3 guideline-indicated medications was higher in attendees of CR at all time points. CONCLUSIONS: Participation in CR among survivors of ACS was associated with reduced all-cause mortality and increased MI readmissions across 3 years post-discharge. The findings underscore the importance of systematic secondary prevention strategies to mitigate mortality risks after ACS.