Attending cardiac rehabilitation linked with improved long-term outcomes in Medicare beneficiaries

Patients with coronary heart disease who attended a greater amount of cardiac rehabilitation sessions had better long-term outcomes, new study results suggested.

Researchers evaluated data from a national 5% sample of 30,161 Medicare beneficiaries who attended at least one outpatient cardiac rehabilitation session between January 1, 2000 and December 31,2005. The primary exposure of interest was the number of rehabilitation sessions reimbursed by Medicare for each patient, with the primary outcome designated as all-cause death. The researchers also examined subsequent MI.

Patients attended a median of 25 rehabilitation sessions, according to results. A total of 8,560 patients were hospitalized at some point during the 36-month period following index hospitalization, of whom 2,676 (31%) resumed attending rehabilitation after discharge. Following adjustment for demographic characteristics, comorbid conditions and subsequent hospitalization, the researchers reported that patients attending at least 36 sessions had a 14% reduction in the risk for all-cause mortality (HR=0.86; 95% CI, 0.77-0.97) and a 12% reduced risk for MI (HR=0.88; 95% CI, 0.83-0.93) vs. patients attending 24 sessions. Patients attending at least 36 sessions had a 22% lower risk for death (HR=0.78; 95% CI, 0.71-0.87) and 23% lower risk for MI (HR=0.77; 95% CI, 0.69-0.87) when compared with those attending 12 sessions. Patients attending >36 sessions had a 47% reduction in the risk for death (HR=0.53; 95% CI, 0.48-0.59) and a 31% lower risk for MI (HR=0.69; 95% CI, 0.58-0.81) when compared to those who attended just one rehabilitation session.

“Among Medicare beneficiaries, a significant dose-response relationship exists between the number of cardiac rehabilitation sessions attended and long-term outcomes,” the researchers concluded. “Our findings suggest that physicians should promote greater use of cardiac rehabilitation services and should strive to understand the barriers that prevent patients from attending the sessions to which they are entitled.”

In an accompanying editorial, William Weintraub, MD, chair of cardiology at Christiana Center for Outcomes Research in Newark, Del., noted that while the statistical methods used in the study were sophisticated, the interpretation may have been affected by confounding data.

“The baseline administrative databases are not as detailed or reliable as data from clinical databases,” he wrote in the editorial. “Thus, if sicker patients or disadvantaged patients drop out of rehabilitation early, they may also have increased risk or recurrent events. If such factors cannot be accounted for, the relationship between how many times patients went to rehabilitation and subsequent outcome may not be reliable.”

Hammill B. Circulation. 2009;doi:10.1161/CIRCULATIONAHA.109.876383.