Smartphone apps deliver small benefits on weight loss

While smartphone apps have the potential to aid weight management in Singapore, their demonstrated effects have so far been small to moderate, according to a recent meta-analysis.

“More evidence is required to determine the efficacy of apps in the long term and address the low uptake of apps to maximize the potential of the intervention,” the researchers said. “Future research should determine the efficacy of each component of the multicomponent intervention to facilitate the designing of studies that are most effective and cost-efficient for weight management.”

Twenty-one eligible studies were retrieved from the online databases of Embase, Medline, CINAHL, PsycINFO, Global Health, and the Cochrane Central Register of Controlled Trials, of which 14 qualified for quantitative analysis. Most (n=17; 81 percent) of the studies were randomized controlled trials (RCT). Overall, data from 21,173 participants (mean age 45.9±9.84 years, 45.1 percent women) were included.

In quantitative analysis, nine studies reported that smartphone interventions had a positive effect on weight loss. On the other hand, studies that found no significant between-arm differences in weight loss nevertheless reported that the intervention contributed to nominally greater weight loss relative to controls. [J Med Internet Res 2021;23:e28185]

Cumulative analysis of the 14 studies showed that despite achieving statistical significance, mobile apps exerted only a small to moderate effect size on weight change (Hedges g, –0.26, 95 percent confidence interval [CI], –0.41 to –0.11; p<0.01) with substantial heterogeneity of evidence. A similarly weak but significant effect was reported for body mass index (BMI; Hedges g, –0.21, 95 percent CI, –0.42 to –0.01; p=0.04) and waist circumference (Hedges g, –0.24, 95 percent CI, –0.45 to –0.02; p=0.03).

In absolute terms, pooled analysis showed that participants receiving the intervention dropped 1.16 kg of body weight (95 percent CI, 0.81–1.52), 0.42 kg/m² of BMI (95 percent CI, 0.16–0.68), and 1.21 cm of waist circumference (95 percent CI, 0.22–2.21) relative to controls.

Subsequent subgroup analysis revealed that even when mobile apps were added to usual care, their impact on weight change remained small to moderate, though statistically significant (Hedges g, –0.28, 95 percent CI, –0.47 to –0.09; p<0.01). Moderation analysis also revealed that intervention or study duration did not significantly modify the effect of smartphone interventions on weight loss.

“This review contributes to the literature by presenting quantitative evidence that multicomponent interventions that incorporate apps produce a small to moderate effect toward weight loss in studies of Asian populations with intervention periods of 6 months or less,” the researchers said, adding that “more evidence is required to determine the efficacy of apps in the long term.”

“Cultural adaptation and offering the app in the native language of the users seem to be a priority in Asian apps. Multifunctional apps with features that include self-monitoring, individualized feedback, and a link to health professionals within the apps may be key to raising awareness and engagement, as well as promoting weight loss,” they added.