JMIR Publications

ABSTRACT

Background:

Cardiac rehabilitation (CR) is an evidence-based multicomponent intervention. However, participation in, and reach of, CR remain suboptimal globally. Digital CR is a promising alternative to traditional centre-based CR, with the potential to increase intervention reach and efficiency. However, efforts to increase the efficiency of digital CR require an understanding of the relative effectiveness of the components of CR, which is currently lacking. The Multiphase Optimization Strategy provides a framework to evaluate the effects of individual components within complex interventions.

Objective:

This mixed methods study explored the feasibility and acceptability of conducting a fully powered optimisation randomised controlled trial (RCT) of a digital CR intervention.

Methods:

Patients attending CR in a community setting were randomised to one of eight experimental conditions in a 2x2x2 (23) factorial trial design. Each condition received a different combination of three intervention components over a six-week study period: (1) goal setting and self-monitoring; (2) education; and (3) feedback messages. Feasibility was assessed through intervention fidelity (e.g., usage statistics) and outcome measure data completeness; acceptability was measured using the System Usability Scale (SUS), a questionnaire, and semi-structured interviews based on the Theoretical Framework of Acceptability.

Results:

Eight participants were recruited and retained in the study. The mean age was 75 years (SD = 5.6), and the majority were female (62.5%, N = 5). The digital CR intervention demonstrated good usability (SUS = 72.1, SD = 19.1), and 83.3% (N = 5) of participants found the digital technology acceptable. However, only half (50%, N = 2) found the feedback messages acceptable. Fidelity was high for goal setting/self-monitoring and feedback, but lower for education. Qualitative findings indicated that participants held positive attitudes towards the intervention and reported improvements in physical activity, although many expressed a preference for more tailored feedback and two-way communication. Of the three pre-specified progression criteria, usability met the ‘Go’ criterion, while intervention fidelity and acceptability, and outcome measure data completeness met the ‘Amend’ threshold.

Conclusions:

This study demonstrated the feasibility of conducting a factorial trial of a digital CR intervention. While the intervention was generally acceptable, modifications to the education and feedback components are necessary. A pilot optimisation RCT is needed to resolve remaining uncertainties and inform the design of a full-scale optimisation trial.