Association Between Cardiac Rehabilitation Participation and Health Status Outcomes After Acute Myocardial Infarction.

IMPORTANCE: Cardiac rehabilitation (CR) improves survival after acute myocardial infarction (AMI), and referral to CR has been introduced as a performance measure of high-quality care. The association of participation in CR with patients' health status (eg, quality of life, symptoms, and functional status) is poorly defined.
OBJECTIVE: To examine the association of participation in CR with health status outcomes after AMI. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study was conducted of patients enrolled in 2 AMI registries: PREMIER, from January 1, 2003, to June 28, 2004, and TRIUMPH, from April 11, 2005, to December 31, 2008. The analytic cohort was restricted to 4929 patients with data available on baseline health status, 6- or 12- month follow-up health status, and participation in CR. Data analysis was performed from 2014 to 2015. EXPOSURES: Participation in at least 1 CR session within 6 months of hospital discharge. MAIN OUTCOMES AND MEASURES: Patient health status was quantified using the Seattle Angina Questionnaire (SAQ) and the 12-Item Short-Form Health Survey (SF-12). The primary outcomes of interest were the mean differences in SAQ domain scores during the 12 months after AMI between patients who did and did not participate in CR. Secondary outcomes were the mean differences in the SF-12 summary scores and all-cause mortality.
RESULTS: After successfully matching the cohorts of the 4929 patients (3328 men and 1601 women; mean [SD] age, 60.0 [12.2] years) for the propensity to participate in CR and comparing the groups using linear, mixed-effects models, mean differences in the SAQ and SF-12 domain scores were similar at 6 and 12 months between the 2012 patients participating in CR (3 were unable to be matched) and the 2894 who did not participate (20 were unable to be matched). At 6 months, the mean difference was -0.76 (95% CI, -2.05 to 0.52) for the SAQ quality of life score, -1.53 (95% CI, -2.57 to -0.49) for the SAQ angina frequency score, 0.38 (95% CI, -0.51 to 1.27) for the SAQ treatment satisfaction score, -0.42 (95% CI, -1.65 to 0.79) for the SAQ physical limitation score, 0.50 (95% CI, -0.22 to 1.22) for the SF-12 physical component score, and 0.13 (95% CI, -0.53 to 0.79) for the SF-12 mental component score. At 12 months, the mean difference was -0.89 (95% CI, -2.20 to 0.43) for the SAQ quality of life score, -1.05 (95% CI, -2.12 to 0.02) for the SAQ angina frequency score, 0.38 (95% CI, -0.54 to 1.29) for the SAQ treatment satisfaction score, -0.14 (95% CI, -1.41 to 1.14) for the SAQ physical limitation score, 0.17 (95% CI, -0.57 to 0.92) for the SF-12 physical component score, and 0.12 (95% CI, -0.56 to 0.80) for the SF-12 mental component score. In contrast, the hazard rate of all-cause mortality (up to 7 years) associated with participating in CR was 0.59 (95% CI, 0.46-0.75). CONCLUSIONS AND RELEVANCE: In a cohort of 4929 patients with AMI, we found that those who did and did not participate in CR had similar reported health status during the year following AMI; however, participation in CR did confer a significant survival benefit. These findings underscore the need for increased use of validated patient-reported outcome measures to further examine if and how health status can be maximized for patients who participate in CR.