The Impact of Cardiac Rehabilitation and Secondary Prevention Programs on 12-Month Clinical Outcomes: A Linked Data Analysis

Background Guidelines recommend referral to cardiac rehabilitation (CR) for cardiac event prevention and risk factor management, but poor attendance persists. Following the development of standardised data and uniform capture, CR services have contributed to three audits in South Australia, Australia. We aimed to determine if CR attendance impacts on cardiovascular readmission, morbidity and mortality. Methods In a retrospective cohort study, CR databases were linked to hospital administrative datasets to compare the characteristics and outcomes of CR patients between 2013 and 2015. Inverse probability weighting methods were used to measure associations between CR attendance versus non-attendance and cardiovascular readmission and the composite of death, new/re-myocardial infarction, atrial fibrillation, heart failure and stroke within 12-months. Results Of 49,909 eligible separations, 15,089/49,909 (30.2%) were referred to CR with an attendance rate of 4,286/15,089 (28.4%). Referred/declined patients were older (median: 67.3 vs 65.3 years, p < 0.001), more likely to be female (32.3% vs 26.5%, p < 0.001) with more heart failure (17.1% vs 10.9%, p < 0.001) and arrhythmia (6.1% vs 2.1%, p <0.001) admissions and higher socio-economic disadvantage (median Index of Relative Socioeconomic Advantage and Disadvantage (IRSAD): 950.1 vs 960.4, p <0.001). Referred/attended patients had lower cardiovascular readmission, (referred/attended vs not referred: 15.6% vs 22.7% and referred/attended vs referred/declined: 15.6% vs 29.6%, p <0.001). After clinical and social factors adjustment there was no difference in composite outcomes, but attendance was associated with reduced cardiovascular readmission (HR:0.68, 95% IQR: 0.58-0.81, p = 0.001). Conclusions Audit can measure service effectiveness, identifying areas for improvement. This study highlights patient eligibility, system and program considerations for future CR services.