Effects of inpatient and outpatient cardiac rehabilitation on the 5-year prognosis in patients with acute myocardial infarction

Aims Cardiac rehabilitation (CR) has been shown to improve the prognosis of patients with acute myocardial infarction (AMI). In Japan, the duration of hospitalization has shortened, resulting in a lower participation rate in CR among outpatients. Therefore, we evaluated the effects of CR, stratified into inpatient and outpatient phases, on the prognosis of patients with AMI in Japan.Methods and results A multi-centre, retrospective, cohort study in which extracted 4411 AMI patients from 72 institutes throughout Japan who were identified from a Japanese Registry Of All cardiac and vascular Diseases (JROAD) in 2014 was performed. The JROAD is a database from Diagnosis Procedure Combination, and we additionally investigated the detailed information about severity, complications, treatment of AMI, the results of examinations, and the 5-year prognosis with respect to CR (JROAD-CR). The patients were divided into four groups, depending on their history of CR as inpatients and outpatients. The percentages of inpatients and outpatients who received CR were 66.1% (n = 2917) and 9.91% (n = 437), respectively. The groups in which only inpatients received CR [In(+)Out(-)] and in which both inpatients and outpatients received CR [In(+)Out(+)] showed significant reductions in composite major adverse cardiovascular events [In(+)Out(-) group; hazard ratio (HR): 0.751, 95% confidence interval (CI) (0.584-0.967) and In(+)Out(+) group; HR: 0.641, 95% CI (0.426-0.964)] and all-cause mortality [In(+)Out(-) group; HR: 0.720, 95% CI (0.546-0.950) and In(+)Out(+) group; HR: 0.575, 95% CI (0.338-0.977)].Conclusion This JROAD-CR study revealed that even short periods of CR during hospitalization are important and continuing CR into the outpatient phase may further improve the prognosis of patients with AMI. In acute myocardial infarction (AMI), short-term prognosis has been improved by early reperfusion therapy; however, the secondary prevention programme for long-term prognosis is still needed. Cardiac rehabilitation (CR) has a class I recommendation and one of the best treatments for secondary prevention. Recently, the balance of CR for inpatients and outpatients has been changing, because early reperfusion therapy has shortened hospitalization days. For the study, we randomly extracted 4411 AMI patients from Japanese nationwide database and additionally registered the data about CR and follow-up data during 5 years. In this study, we investigated the effectiveness of CR divided into inpatients and outpatients against the prognosis of AMI in the era of short hospitalization days. Inpatient CR reduced 24.9% composite major adverse cardiovascular events, 28.0% all-cause mortality, and 24.9% readmission by cardiovascular diseases.Inpatient CR, followed by outpatient CR, reduced 35.9% composite major adverse cardiovascular events, 42.5% all-cause mortality, and 35.2% readmission by cardiovascular diseases.