Abstract
Background: Cardiovascular disease (CVD) is the leading cause of death worldwide. Cardiac rehabilitation (CR) is a complex intervention that aims to stabilise, slow, or reverse the progression of CVD and improve patients' functional status and quality of life. Digitally delivered CR has been shown to be effective and can overcome many of the access barriers associated with traditional centre-based delivered CR programmes. However, there is a limited understanding of the behaviour change techniques (BCTs) and intervention features that maximise the effectiveness of digital programmes. Therefore, this systematic review will aim to identify the BCTs that have been used in digital CR programmes and to determine which BCTs and intervention features are associated with programme effectiveness. Methods: PubMed, MEDLINE (Ovid), EMBASE, CINHAL, PsycINFO and Cochrane Central Register of Controlled Trials will be searched from inception to June 2021 for randomised controlled trials of digital CR with CVD patients. Screening, data extraction, intervention coding and risk of bias will be performed by one reviewer with a second reviewer independently verifying a random 20% of the articles. Intervention content will be coded using the behaviour change technique taxonomy v1 and the Template for Intervention Description and Replication (TIDieR) checklist and intervention features will be identified. A meta-analysis will be conducted to calculate the pooled effect size of each outcome, and meta-regression analyses will investigate whether intervention features and the presence and absence of individual BCTs in interventions are associated with intervention effectiveness. Discussion: The review will identify BCTs and intervention features that are associated with digital CR programmes and adopt a systematic approach to describe the content of these programmes using the BCT taxonomy (v1) and TIDieR checklist. The results will provide key insights into the content and design of successful digital CR programmes, providing a foundation for further development, testing and refinement.