Completion of cardiac rehabilitation leads to improved clinical outcomes in 10954 patients within 365 days following an acute coronary syndrome or revascularization procedure admission

Type of funding sources: Public Institution(s). Main funding source(s): NHMRC

Cardiac rehabilitation (CR) can prevent 1 in every 17 cardiovascular deaths after a heart attack. However globally, only 28-50% of the eligible patients complete a program. Low attendance might compromise CR effectiveness in the real world.

To investigate CR utilization and clinical outcomes after an acute coronary syndrome (ACS), coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI).

A retrospective cohort study design selected patients >=18 years discharged from public hospitals with a diagnosis of ACS, CABG or PCI from 2016-2021. The statewide clinical CR database was linked with hospital administrative and death databases. CR utilization was measured by attendance (i.e., participation in >= one session) and completion (i.e., participation in >= 70% of the required sessions). The primary outcome was a composite of all-cause death and re-admission for myocardial infarction, heart failure, atrial fibrillation or stroke within 365 days following the index hospitalization. To investigate whether attendance and completion compared to non-referral were associated with the primary outcome, a time-dependent Cox survival model was adjusted for age (time-dependent variable), sex; Index of Relative Socioeconomic Advantage and Disadvantage, remoteness; ACS, CABG, PCI, heart failure, atrial fibrillation, other arrhythmias, valve or implantable devices procedures at the index admission; Charlson comorbidities index, time of admission (pre vs during the COVID-19 pandemic). This project received Ethics approval from the South Australian Department for Health and Wellbeing (2021/HRE00270).

Of the 10954 separations, 4539 (41.4%) were referred but declined CR. Among those commencing, 759 (22.0%) attended at least one session but did not complete the program and 2687 (78.0%) completed the program. Median waiting time to commence CR was 38 days (IQR 23-63). Participants were predominantly male (70.9%). Mean age was 66 (13.7) years. CABG (961; 8.8%) and PCI (5370; 49.0%), diabetes (3138; 28.6%), hypertension 1298 (11.8%) and heart failure (1055; 9.6%) were common diagnoses. Women were less likely to be referred than men (61.4%; vs 77.7%; p<0.001). There were 1760 (16.1%) primary outcome events. Compared to those not referred to CR and after adjustment for demographic, clinical and social factors, patients completing CR had a lower risk of overall mortality/cardiovascular re-admission within 12 months (HR 0.72; 95%CI 0.62-0.84; p<0.001). Attending without completing (HR 0.88; 95%CI 0.69-1.12; p = 0.29) was not associated with the primary outcome.

CR is effective in reducing major cardiovascular events for those completing a program after an ACS or revascularization procedure. Reduction of waiting times and promoting women participation might extend CR benefits to all eligible patients.