Effectiveness of gamified team competition in the context of mHealth intervention for medical interns: a micro-randomized trial

Background: Twin revolutions in wearable technologies and smartphone-delivered digital health interventions have significantly expanded the accessibility and uptake of personalized interventions in multiple domains of health sciences. Gamification, the application of gaming elements to increase enjoyment and engagement, has the potential to improve the effectiveness of digital health interventions. However, the effectiveness of competition gamification components remains poorly understood, challenging informed decisions on the potential adoption of these components in future studies and trial designs. We aimed to evaluate the effect of smartphone-based gamified team competition intervention on daily step count and sleep duration via a micro-randomized trial. Methods: We recruited first-year medical residents (interns) in the US, who downloaded the study app, provided consent, wore a wearable device, and completed a baseline survey. Teams were formed based on participating residents' institutions and specialties, and subsequently randomized weekly to the competition or non-competition arms. In the competition arm, opponent teams and competition type (step count or sleep duration) were also randomly selected. Competition participants had access to the current competition scoreboard and competition history via the study app; they also received scheduled competition-related push notifications in a competition week. We estimated the main and moderated causal effects of competition on proximal daily step count and sleep duration. This trial is registered with ClinicalTrials.gov (NCT05106439). Findings: Between April and June 2020, we enrolled 2,286 medical interns from 263 institutions, of whom 1,936 were formed into 191 teams that met the criteria for participation in competitions between July 6 and September 27, 2020. 1,797 participants who had pre-internship baseline information were included in the analysis. Relative to the no competition arm, competition intervention significantly increased the mean daily step count by 111.5 steps (SE 40.4, p=0.01), while competition did not significantly affect the mean daily sleep minutes (p=0.69). Secondary moderator analyses indicated that, for each additional week-in-study, the causal effects of competition on daily step count and sleep minutes decreased by 9.1 (11.6) steps (p=0.43) and 1.9 (0.6) minutes (p=0.003), respectively. Intra-institutional competition negatively moderated the causal effect of competition upon daily step count by -114.9 (93.7) steps (p=0.22). Interpretation: Gamified competition delivered via mobile app significantly increased daily physical activity which suggests that team competition can function as a mobile health intervention tool to increase short-term physical activity level.