JMIR Publications

ABSTRACT

Background:

Digital health interventions (DHIs) have demonstrated effectiveness in improving poor nutrition, physical inactivity and overweight/obesity. Evidence suggests the impact of DHIs may be enhanced by improved user engagement, however little is known about overall effectiveness of strategies on engagement with DHIs.

Objective:

The primary aims were to (i) assess the overall effectiveness of strategies to improve user engagement (usage and user experience) with DHIs targeting nutrition, physical activity, and overweight/obesity; and (ii) explore the association between individual strategies and engagement outcomes. The secondary aim was to explore the impact of strategies on health risk outcomes (nutrition, physical activity, overweight/obesity).

Methods:

MEDLINE, Embase, PsycINFO, CINAHL, CENTRAL, Scopus and Academic Source Complete were searched up to 24th July 2023. Eligible studies were required to be a randomised controlled trial design, evaluate strategies to improve user engagement with DHIs targeting nutrition, physical activity or overweight/obesity, and report any usage or user experience outcomes related to DHI engagement. Strategies to improve engagement were classified according to Behaviour Change Techniques (BCTs) and design features (eg, emails, videos). Multiple variable meta-analyses of both primary review outcomes (usage and user experience) were undertaken to assess the overall effectiveness of strategies to improve engagement. Meta-regressions were conducted to assess the association between individual strategies and both usage and user experience outcomes. The synthesis of secondary outcomes (ie, nutrition, physical activity, overweight/obesity) followed the 'Synthesis without meta-analysis' guidelines. Methodological quality of studies was assessed using Cochrane’s Risk of Bias tool and quality of evidence was assessed using the Grading quality of evidence and strength of recommendations tool (GRADE).

Results:

In total, 54 studies (across 62 publications) met inclusion criteria. Pooled analysis found very low certainty evidence of a small to moderate positive effect of the use of strategies overall to improve DHI usage (SMD 0.33; 95% CI 0.20-0.46; P<.01). Pooled analyses found very low certainty evidence for a small to moderate positive effect of strategies overall on user experience (SMD 0.29; 95% CI 0.07-0.52; P=.012). A significant positive association was found between the BCTs social support (ES 0.40; 95% CI 0.14-0.66; P<.001), and shaping knowledge (ES 0.39; 95% CI 0.03-0.74 P=0.03) and DHI usage. A significant positive association was found between the BCTs social support (ES 0.70; 95% CI 0.18-1.22; P=0.01), repetition and substitution (ES 0.29; 95% CI 0.05-0.53 P=0.03) and natural consequences (ES 0.29; 95% CI 0.05-0.53; P=0.02); and design features of email (ES 0.29; 95% CI 0.05-0.53; P=0.02) and short message service (SMS) ES 0.34; 95% CI 0.11-0.57; P=0.01) and DHI user experience. For secondary outcomes, 44% of nutrition-related outcomes, 65% of physical activity-related outcomes and 39% of overweight/obesity-related outcomes were in the hypothesised direction (ie, reported an improvement in health outcomes).

Conclusions:

While positive results suggest that the use of strategies overall may improve engagement with DHIs targeting nutrition, physical activity and overweight/obesity, the true effect is unknown due to very low certainty of evidence. Future research exploring whether specific forms of social support, repetition and substitution, natural consequences, emails and SMS have a greater impact on DHI engagement is warranted.