Survival Benefits of Outpatient Cardiac Rehabilitation after Acute Myocardial Infarction: Propensity Analysis Using Japanese Administrative Database

Abstract

BACKGROUND: Survival benefit of outpatient cardiac rehabilitation (CR) after acute myocardial infarction (AMI) has recently been contested under the current real-world clinical practice. We investigated whether outpatient CR was associated with lower mortality and morbidity risks among Japanese AMI patients. METHODS: We analyzed patients who were admitted for AMI and received both percutaneous coronary intervention and inpatient CR from January 2011 to December 2014, using a nationwide administrative database in Japan (final date of follow-up: July 31, 2016). We compared patients who received outpatient CR and who did not, and the primary outcome was a composite of all-cause death and recurrence of AMI after the landmark time-point of day 180 after discharge. We applied Cox proportional hazards model to estimate outcomes, and propensity-score matching was applied to adjust for baseline imbalances. RESULTS: A total of 5, 654 patients (mean [SD] age, 66.8 [12.4] years; 21.2% female; median follow-up period [IQR] 1.44 [0.87, 2.27] years), 730 (12.9%) participated in outpatient CR at least once within 180 days of discharge. Of 1, 458 propensity-score matched patients, outpatient CR participation was associated with lower but statistically non-significant risks among the primary outcome (1.38 vs. 2.12 per 100 patient-years; HR = 0.71; 95%CI, 0.32 to 1.61). CONCLUSIONS: Among Japanese patients who admitted for AMI and received both percutaneous coronary intervention and inpatient CR, outpatient CR was underutilized, and associated with a statistically non-significant mortality and morbidity benefits. Further study is necessary to reaffirm the real-world effectiveness of outpatient CR under the current real-world clinical practice.