Abstract
BACKGROUND: Research on technology acceptance and use in e-health weight-loss interventions is limited. Using data from a randomized controlled trial of two e-health interventions, we evaluated the acceptance and use of a self-monitoring Web site for weight loss. MATERIALS AND METHODS: We examined eight theoretical constructs about technology acceptance using adapted 5-point Likert scales and the association of measured Web site usage and weight loss. RESULTS: All scales had high internal consistency (Cronbach's alpha=0.74-0.97) in both interventions and at 3 and 15 months (end of intensive and maintenance intervention, respectively). From 3 to 15 months mean scores changed unfavorably for two constructs (compatibility and behavioral intention) among coach-led intervention participants, who received ongoing feedback on their self-monitoring entries. Among self-directed intervention participants, who received minimal coach support, mean scores changed unfavorably for five constructs (usefulness, ease of use, concern, compatibility, and behavioral intention). At 3 months, usefulness, ease of use, effect, compatibility, and behavioral intention in the coach-led group (Pearson r=0.33-0.5) and usefulness and affect in the self-directed group (r=0.43-0.46) were significantly correlated with Web site usage, which was correlated with weight loss (β=-0.02, p≤0.001 for both interventions). From 3 to 15 months, mean score changes for usefulness and behavioral intention correlated significantly with Web site usage in the coach-led group. CONCLUSIONS: The adapted acceptance measures showed acceptable psychometric properties and significant associations with actual Web site use, which correlated with weight loss. Better understanding of technology acceptance and use in e-health weight-loss interventions may improve participant adherence and outcome.