Background: Cardiac and pulmonary rehabilitation programs are grossly underutilized, and participation is particularly low in rural regions.

Methods: We are conducting a 2-arm, randomized controlled feasibility trial. Eligible participants include older frail adults with cardiac or pulmonary disease living in a predominantly rural county in western Massachusetts. Participants are randomized 1:1 to treatment as usual or stepped care. Patients randomized to treatment as usual participate in twice weekly center-based rehabilitation sessions over eight weeks and are encouraged to exercise at home in between sessions. Patients randomized to the stepped-care arm are offered/enrolled in the center-based rehabilitation program followed by possible step up to three interventions based on prespecified non-response criteria: 1) Transportation-assisted center-based rehabilitation, 2) Home-based telerehabilitation, and 3) Community health worker-supported home-based telerehabilitation. The primary feasibility outcomes are average number of eligible patients randomized per month, baseline measure completion, proportion attending at least 70% of the prescribed sessions, average number of sessions attended in the stepped-care arm, and proportion in the stepped-care arm completing patient reported outcome measures. Each of these process indicators is evaluated by preset "Stop" and "Go" thresholds.

Conclusion: The proposed stepped-care model is an efficient, patient-centered, approach to expanding access to cardiac and pulmonary rehabilitation. Meeting the "Go" thresholds for the prespecified process indicators will justify conducting a definitive full-scale randomized controlled trial to compare the effectiveness and value (cost-effectiveness) of stepped-care versus center-based rehabilitation in older frail adults living rural counties.