Abstract 4366999: Optimizing Representation and Retention in Hybrid Cardiac Rehabilitation: Lessons Learned from the mTECH-Rehab Randomized Controlled Trial

Background: Cardiac rehab (CR) is a critical but underused secondary prevention program. Hybrid CR programs have the potential to improve patient access by enabling home CR sessions alongside traditional in-center sessions. However, representation and retention of patients who enroll in hybrid CR remain a knowledge gap. Methods: The mTECH-Rehab trial evaluated a 12-week hybrid CR program (center and home-based), recruiting from four inpatient sites, with outpatient delivery at affiliated and unaffiliated centers based on patient preference. We integrated strategies informed by early pilot data to facilitate representative enrollment and retention. These included remote recruitment with electronic consent, a pre-randomization run-in period, and human-centered design paired with digital engagement workflows. Participants in the intervention arm received necessary devices (smartphones, smartwatches, blood pressure monitors) to mitigate digital access barriers. Trained tech coaches ran personalized onboarding guided by a structured protocol, with on-demand participant support throughout the trial. A 4-week run-in period ensured continued interest and digital readiness. Weekly metrics included screening, enrollment, dropout, and randomization to inform adaptive outreach (Fig. 1 ). Results: Of 6,170 patients screened, 1,252 (19%) met eligibility criteria; 969 (77%) were contacted, and 259 (27%) enrolled (mean [SD] age 65 [11.7] years). Among those enrolled, 202 (78%) were randomized, and 167 (83%) of these were retained and completed follow-up. Representation by age, sex, and race remained stable across all phases (mean [SD] age = 64 [12] years enrolled and retained; 32% women enrolled, 31% retained; 9% African Americans enrolled, 10% retained), suggesting that access-related barriers did not lead to attrition ( Fig 2) . Reasons for dropout included unavailability for clinical visits (25%), insurance or logistical issues (22%), loss of contact (19%), unreliable follow-up (19%), withdrawal of consent (9%), and health issues (7%). Conclusion: In our trial, despite low enrollment of racial and ethnic groups, demographic retention and representation in hybrid CR by age, sex, and race were stable. This is an encouraging result achieved through a multifaceted strategy that included a run-in phase, digital device provision, supportive onboarding, and on-demand technology support. Whether such stability can be achieved in a real-world implementation requires further investigation.