Accuracy of Self-Reported Weight Collected Through a Web-Based Platform in a Weight Loss Trial: Validation Study of the POEmaS Clinical Trial.

Self-reported anthropometric data in web-based weight loss interventions may be inaccurate. We studied the agreement between online self-reported and measured weight in the course of the POEmaS randomized controlled trial. Measured weight was not different from reported one (-0.4 kg; 95%CI -0.93 to 0.12). 95.6% of the cases were within the limits of agreement (Bland-Altman method). Self-reported weight collected online was accurate, which suggests that interventions and outcomes assessment can rely on these data.

Exploring the User Engagement Scale Short Form as a Determinant of Adherence in Digital Health Interventions.

Adherence determines the impact of digital health interventions. Standard tools provide a measure for user experience and predict adherence. We evaluated the User Engagement Scale Short Form (UES-SF) during the POEmaS project, a randomized clinical trial of an online weight loss platform. We received answers from 178 participants (13.7% of the cohort) and correlated the UES-SF scores with the number of sessions attended. Our findings suggest the UES-SF is an accurate evaluation of user experience, but only one domain (reward) was associated with long-term use.