Efficacy of the Aim2Be app in changing lifestyle behaviours among adolescents with overweight and obesity: Randomized Controlled Trial (Preprint)

BACKGROUND Aim2Be is a gamified lifestyle app designed to promote lifestyle behaviour change among Canadian adolescents and their families. OBJECTIVE Our primary aim was to test the efficacy of the Aim2Be app with support from a live coach to reduce weight outcomes (Body Mass Index Z-score (zBMI)) and improve lifestyle behaviours among adolescents with overweight and obesity and their parents versus a waitlist control group over 3 months. Secondary aims were to compare health trajectories among waitlist control participants over 6 months (before and after receiving access to the app), assess whether support from a live coach enhanced intervention impact, and evaluate app usage influenced changes among intervention participants. METHODS A 2-arm parallel randomized control trial was conducted from November 2018 to June 2020. Adolescents aged 10-17 years with overweight or obesity and their parents were randomized into an intervention group (Aim2Be with live coach for 6 months) or a waitlist control group (Aim2Be with no live coach; accessed after 3 months). Adolescents’ assessments at baseline, 3- and 6- months included measured height and weight, 24-hour dietary recalls, and daily step counts measured with a Fitbit. Self-reported physical activity, screen time, fruit and vegetable intake, and sugary beverage intake of adolescents and parents were also collected. RESULTS A total of 214 parent-child participants were randomized. In our primary analyses, there were no significant differences in zBMI or any of the health behaviours between the intervention and control groups at 3 months. Secondary analyses revealed that among waitlist control participants, zBMI (mean difference between phases: -0.10; P=0.023) and discretionary calories (mean difference between phases: -5.8%; P=0.033) declined after receiving app access compared to before receiving app access. Adolescents randomized to Aim2Be with coaching reported more time being active outside of school compared to adolescents who used Aim2Be with no coaching over 3 months (P=0.001). App utilization did not modify any changes in outcomes among adolescents in the intervention group. CONCLUSIONS The Aim2Be app did not improve zBMI and lifestyle behaviours in adolescents with overweight and obesity vs. a waitlist control group over 3 months. Future studies should explore the potential mediators of change in zBMI and lifestyle behaviours as well as predictors of engagement. CLINICALTRIAL The trial was prospectively registered at ClinicalTrials.gov (NCT03651284) on 29 August 2018. INTERNATIONAL REGISTERED REPORT RR2-https://doi.org/10.1186/s13063-020-4080-2