Cardiac Rehab Participation and Health Status After Acute MI

Study Questions:

What is the association between participation in cardiac rehabilitation (CR) and health status outcomes after acute myocardial infarction (AMI)?

Methods:

A retrospective cohort study was conducted of patients enrolled in two AMI registries: PREMIER, from January 2003 to June 2004, and TRIUMPH, from April 2005 through December 2008. The analytic cohort was restricted to 4,929 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. 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 up to 7 years after the AMI.

Results:

A total of 2,015 patients (40.9%) reported participation in at least one session of CR within 6 months of hospitalization for AMI. After successfully matching the cohorts of the 4,929 patients (3,328 men and 1,601 women; mean [standard deviation] 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 and the 2,894 who did not participate. At 6 and 12 months, there was no difference for the SAQ quality-of-life score, the SAQ angina frequency score, the SAQ treatment satisfaction score, the SAQ physical limitation score, the SF-12 physical component score, or 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% confidence interval, 0.46-0.75) or a 41% decrease in mortality.

Conclusions:

In a cohort of 4,929 patients with AMI, participation in CR had no influence on the 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.

Perspective:

This is an important observational study using propensity scoring to reduce bias associated with CR referral and participation. Among the limitations include the binary definition of CR participation as none or at least one session, and lack of data regarding the CR program(s) assessment of and approach to psychological distress. In a study of Medicare beneficiaries, a strong dose-response relationship existed between the number of CR sessions and long-term outcomes (Hammill BG, et al., Circulation 2010;121:63-70), a finding that would likely also impact health status.


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