The impact of in-hospital cardiac rehabilitation program on medication adherence and clinical outcomes in patients with acute myocardial infarction in the Lazio region of Italy

Medication adherence is a recognized key factor of secondary cardiovascular disease prevention. Cardiac rehabilitation increases medication adherence and adherence to lifestyle changes. This study aimed to evaluate the impact of in-hospital cardiac rehabilitation (IH-CR) on medication adherence as well as other cardiovascular outcomes, following an acute myocardial infarction (AMI). This is a population-based study. Data were obtained from the Health Information Systems of the Lazio Region, Italy (5 million inhabitants). Hospitalized patients aged ≥ 18 years with an incident AMI in 2013-2015 were investigated. We divided the whole cohort into 4 groups of patients: ST-elevation AMI (STEMI) and non-ST-elevation AMI (NSTEMI) who underwent or not percutaneous coronary intervention (PCI) during the hospitalization. Primary outcome was medication adherence. Adherence to chronic poly-therapy, based on prescription claims for both 6- and 12-month follow-up, was defined as Medication Possession Ratio (MPR) ≥ 75% to at least 3 of the following medications: antiplatelets, β-blockers, ACEI/ARBs, statins. Secondary outcomes were all-cause mortality, hospital readmission for cardiovascular and cerebrovascular event (MACCE), and admission to the emergency department (ED) occurring within a 3-year follow-up period. A total of 13.540 patients were enrolled. The median age was 67 years, 4.552 (34%) patients were female. Among the entire cohort, 1.101 (8%) patients attended IH-CR at 33 regional sites. Relevant differences were observed among the 4 groups previously identified (from 3 to 17%). A strong association between the IH-CR participation and medication adherence was observed among AMI patients who did not undergo PCI, for both 6- and 12-month follow-up. Moreover, NSTEMI-NO-PCI participants had lower risk of all-cause mortality (adjusted IRR 0.76; 95% CI 0.60-0.95), hospital readmission due to MACCE (IRR 0.78; 95% CI 0.65-0.94) and admission to the ED (IRR 0.80; 95% CI 0.70-0.91). Our findings highlight the benefits of IH-CR and support clinical guidelines that consider CR an integral part in the treatment of coronary artery disease. However, IH-CR participation was extremely low, suggesting the need to identify and correct the barriers to CR participation for this higher-risk group of patients.