Despite national guidelines strongly supporting the use of cardiac rehabilitation (CR) in patients after they suffer an acute myocardial infarction (AMI), many trials have shown that participation in such programs is relatively low. Some research has questioned the value of CR among AMI patients because studies have not consistently shown that these programs can lead to mortality benefits. “Compounding the issue is the fact that CR programs are often considered costly and inconvenient for patients,” says Jacob A. Doll, MD. “As such, data are needed in which outcomes associated with CR are assessed among AMI patients, especially for high-risk groups like the Medicare population.”
Published estimates have shown that patients aged 65 and older account for more than half of the 15.4 million Americans with heart disease, but these individuals have especially low participation rates in CR programs after AMI. In addition, older adults are underrepresented in prevention trials. Participating in CR has been shown to improve functional capacity and quality of life for older adults, but the optimal number of CR sessions that these patients need to attend in to be beneficial is unclear.
For a study published in the American Heart Journal, Dr. Doll and colleagues examined the characteristics of older individuals with AMI who participated in a greater or lesser number of CR sessions and looked at the association between the number of sessions attended and medication adherence as well as clinical outcomes. “It’s important to note that all participants had attended at least one CR session after their AMI,” Dr. Doll says.
The authors could examine contemporary outcomes because they linked a national AMI registry to Medicare claims data. The study examined Medicare patients who were enrolled in the Acute Coronary Treatment Intervention Outcomes Network Registry-Get With the Guidelines (ACTION Registry-GWTG) from January 2007 to December 2010 and looked at 1 year follow-up. Despite having Medicare coverage and being referred to CR after AMI, only about one-third of patients aged 65 or older participated in a CR program.
“Our results showed that older AMI patients who attended more CR sessions had lower mortality rates and fewer clinical events,” says Dr. Doll. Each five-session increase in CR participation was associated with 13% lower mortality and a reduction in their overall risk of major adverse cardiac events, deaths, and hospital readmission (Table). When compared with patients attending 25 or fewer sessions, those attending 26 or more sessions were more likely to be male, had fewer comorbidities, and underwent prior revascularization. These patients were also more likely to present with ST-segment elevation myocardial infarction.
The analysis also showed that patients with Medicare Part D prescription coverage who went to more CR sessions had better adherence to secondary prevention medications, such as P2Y12 inhibitors and β-blockers, than those attending fewer CR sessions. “Among patients in whom we could assess medication adherence, those who participated in CR were more likely to adhere to their drug regimens,” Dr. Doll says. “Those who attended more CR sessions had higher medication adherence rates even after we adjusted for other clinical variables. It’s possible that this occurred because CR participants were more likely to stick with the behaviors they learned in these programs. It’s also possible that CR participation promotes adherence by providing structure and ongoing education during the post-AMI period.” The study notes that improved medication adherence may also have had a positive effect on survival and future cardiac risk.
More Work Needed
The study expands on the current knowledge regarding the impact of CR on older AMI patients, but more research is still needed. While the analysis observed lower rates of major adverse cardiac events and readmissions with increasing use of CR, this association held true only up to 16 sessions. There was no further reduction in the risk of cardiac events or readmission with more participation in CR. It is possible that the initial CR sessions helped patients avoid recurrent events or admissions during the period after discharge.
“In future research, it would be helpful to determine if longer durations of CR participation may provide other benefits in older AMI patients,” says Dr. Doll. “We also need to explore if alternative programs, such as home-based cardiac rehabilitation, and other technologies, like digital applications, can be effective options to increase enrollment into CR programs. In the meantime, clinicians should continue encouraging older patients who have suffered an AMI to participate in CR even after they initiate participation in these programs. With continued use of CR, we may be able to reduce the burden of AMI in the Medicare population.”