Smartphone Cardiac Rehabilitation, Assisted Self-Management (SCRAM) Versus Usual Care: Multicenter Randomized Controlled Trial

Background: Accessibility barriers contribute to low participation in center-based cardiac rehabilitation. We developed an innovative, comprehensive, dual-phase telerehabilitation program to address this gap (Smartphone Cardiac Rehabilitation, Assisted Self-Management; SCRAM). Objective: The study aimed to determine the effectiveness of SCRAM for increasing maximal aerobic exercise capacity (VO2max). Methods: A multicenter, parallel 2-arm randomized controlled trial recruited clinically stable adults (aged ≥18 y) with diagnosed coronary heart disease at 3 hospitals in Victoria, Australia (Melbourne, Geelong, and Bendigo) from 2018 to 2021. Participants were randomized (1:1), stratified by sex and study site, to receive SCRAM plus usual cardiovascular care (intervention) or usual cardiovascular care alone (control). SCRAM provided 24 weeks of remote exercise supervision, coaching, and behavior change support via smartphone. Usual cardiovascular care included standard medical care and advice to seek a referral to center-based cardiac rehabilitation, which was heavily impacted during the COVID-19 pandemic. Due to the nature of the treatments, participants were not blinded to allocation; primary outcome assessors and biostatisticians were blinded. The primary outcome was VO2max at 24 weeks, analyzed on the principle of intention-to-treat, using linear regression adjusted for baseline and stratification factors on multiple imputed data. Results: Recruitment and data collection were heavily impacted by COVID-19, although SCRAM delivery was sustained throughout. Of 220 required participants, only 123 (56%) were recruited and randomized (intervention n=63, control n=60); 45% (55/123) had missing VO2max at 24 weeks-largely due to enforced COVID-19 restrictions. Mean VO2max at 24 weeks favored SCRAM (26.10, SD 10.72 mL/kg/min) over control (24.65, SD 7.87 mL/kg/min), but the difference was not statistically significant (mean difference=1.61 mL/kg/min, 95% CI -1.38 to 4.61, P=.28). Among secondary outcomes, patients receiving SCRAM had lower diastolic blood pressure at 24 weeks (mean difference=-5.54 mm Hg, 95% CI -10.01 to -1.06). All reported adverse events (control n=6, intervention n=16) were deemed mild or moderate, with only one deemed as possibly related to treatment. There were no deaths or hospitalizations. Conclusions: This was an underpowered trial, but SCRAM did not lead to a clinically important difference in VO2max compared to usual cardiac care. SCRAM was resilient to COVID-19-related disruptions that significantly impacted the delivery of cardiac rehabilitation and supervised exercise training in particular. Further research is needed to conclusively assess treatment effects and understand how virtual cardiac rehabilitation can be translated into routine practice to augment center-based delivery and enhance equity of access.