JMIR Publications

ABSTRACT

Background:

Previous systematic reviews of digital eating disorder interventions have demonstrated effectiveness at improving symptoms of eating disorders, however our understanding of how these interventions work and what contributes to their effectiveness is limited. Understanding the behaviour change techniques which are most commonly included within effective interventions may provide valuable information for researchers and developers. Establishing whether these techniques have been informed by theory will identify whether they target those mechanisms of action which have been identified as core to changing eating disorder behaviours. It will also evaluate the importance of a theoretical approach to digital intervention design.

Objective:

The aim of this study was to define the behaviour change techniques (BCTs) within digital self-management interventions or minimally guided self-help interventions for adults with eating disorders which have been evaluated within randomised controlled trials (RCTs). It also assessed which of the digital interventions were grounded in theory and the range of modes of delivery included.

Methods:

A literature search identified RCTs of digital intervention for the treatment of adults with eating disorders with minimal therapist support. Each digital intervention was coded for behaviour change techniques using the established Behaviour Change Technique Taxonomy (v1); the application of theory using an adapted version of the Theory Coding Scheme and for modes of delivery using the Mode of Delivery Ontology. A meta-analysis evaluated the evidence that any individual BCT moderated effect-size, or that other potential factors such as the application of theory or number of modes of delivery had an effect on eating disorder outcomes.

Results:

Digital interventions included an average of 14 BCTs (range 9-18). “Self-monitoring of behaviour” was included in all effective interventions, with “Problem-solving”, “Information about antecedents”, “Feedback on behaviour”, “Self-monitoring of outcomes of behaviour” and “Action Planning” identified in over 75% of effective interventions. “Social support” and “Information about health consequences” were more evident in effective interventions at follow-up compared with post-intervention. The mean number of modes of delivery was 5 (n=12), with the majority of interventions being web-based. Digital interventions which had a higher score on the Theory Coding Scheme (TCS) had a greater effect size than those with a lower TCS score (subgroup differences: Chi2 = 9.68 , P=.002, I² = 89.7%) within the meta-analysis. No other subgroup analyses had significant results.

Conclusions:

There was a high level of consistency in terms of the most common BCTs within effective interventions, although no evidence that any specific BCT contributed to intervention efficacy. Those interventions which were more strongly informed by theory demonstrated greater improvements in eating disorder outcomes compared to waitlist/treatment-as-usual controls. These results can be used to inform the development of future digital eating disorder interventions.