Association Between Cardiac Rehabilitation and Frailty

Background: Cardiac rehabilitation is a mainstay treatment for patients experiencing an adverse cardiovascular event. Heart disease is important in frailty, but the impact of cardiac rehabilitation on frailty is unclear. Methods: Patients were referred to a 12-week group-based exercise and education cardiac rehabilitation program performed twice weekly. Frailty was measured with the use of a 25-item accumulation of deficits frailty index (range 0-1; higher values indicate greater frailty) at cardiac rehabilitation admission and completion. Patients were categorized by the degree of frailty in 0.1 increments. Results: Of the 4004 patients who enrolled, 2322 (58.0%) completed cardiac rehabilitation with complete data at admission and completion. There were 414 (17.8%), 642 (27.6%), 690 (29.7%), 401 (17.3%), and 175 (7.5%) patients with admission frailty levels of < 0.20, 0.20-0.30, 0.30-0.40, 0.40-0.50, and > 0.50, respectively. Frailty levels improved from cardiac rehabilitation admission (mean 0.34 [95% CI 0.32-0.35]) to completion (0.26 [0.25-0.28]) for those who completed the program (P < 0.001). After adjusting for age, sex, and number of exercise sessions attended, frailty improved in all frailty groups by mean differences of 0.03 (0.02-0.03), 0.05 (0.05-0.06), 0.08 (0.08-0.09), 0.10 (0.09-0.11), and 0.11 (0.10-0.13) in the < 0.20, 0.20-0.30, 0.30-0.40, 0.40-0.50, and > 0.50 frailty groups, respectively. The minimal improvement in frailty scores (>= 0.03 reduction) was achieved by 48%, 65%, 72%, 76%, and 79% of patients in the the 5 frailty groups, respectively. Conclusions: Although higher frailty levels were associated with cardiac rehabilitation drop-out, finishing the program was related to improving frailty levels, especially in patients who were the frailest.