Cardiac rehabilitation attendance and outcomes 3 years after acute coronary syndrome (ACS): Linked national data of the SNAPSHOT ACS audit

Abstract Background In international guidelines, cardiac rehabilitation is recommended to reduce readmissions, mortality and improve disease management. However, evidence from a long-term follow-up in a representative cohort is scarce. Purpose To compare 3-year outcomes among acute coronary syndrome (ACS) survivors who attended cardiac rehabilitation programs and those who did not. Methods This was a follow-up of the SNAPSHOT ACS cohort in 1,920 Australians. Clinical data of those presenting with suspected ACS, hospitalised, discharged alive and followed for 18 months were linked to jurisdictional/national regulatory hospitalisation, mortality and pharmacotherapy records. Outcomes were all-cause and cardiovascular mortality, myocardial infarction (MI) and cardiovascular readmissions. Cox regression was used to analyse all-cause mortality, and Fine and Gray competing risk model for cardiovascular mortality, MI and cardiovascular readmissions, where non-cardiovascular mortality or all-cause mortality were competing events. The models were adjusted for age, sex, discharge diagnosis and coronary revascularisation. Results The cohort was aged 66±13.5 years; 60% were male, 31% had a discharge diagnosis of MI, and 490 (26%) attended cardiac rehabilitation. Cardiac rehabilitation attendees more frequently received coronary revascularisation and had a discharge diagnosis of MI during index admission. Attendees were more likely to be men (70% vs 57%, p<0.001) with a family history of coronary disease (43% vs 36%, p=0.008). The prescription of ≥3 guideline-indicated medications was higher in cardiac rehabilitation attendees. Compared to those who did not attend cardiac rehabilitation, the hazard of all-cause mortality was lower for the attendees (4.3% vs 8.6%, HR: 0.55, 95% CI: 0.34-0.91), but the hazard of MI and cardiovascular readmissions significantly greater in the attendees (17% vs 8.5%, HR: 1.99, 95% CI: 1.41-2.82; 42% vs 33%, HR: 1.34, 95% CI: 1.10-1.63; respectively) (Figure). There was insufficient cardiovascular mortality between groups to fit a statistical model (n=7 (1.4%) vs n=24 (1.7%), p=0.705). Conclusions Survivors of ACS attending cardiac rehabilitation were associated with reduced all-cause mortality and increased readmissions related to MI and cardiovascular disease at 3 years follow-up. These findings support secondary prevention strategies to mitigate mortality risk after ACS.