Clinical Decision Support for Digital Dietary Counseling Under GLP-1 Receptor Agonist Therapy: Convergent Mixed Methods Usability and Treatment Satisfaction Pilot Study of the Personalized Nutrition Advisor.

Background: Dietary counseling is an essential complement to the growing use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) to achieve sustainable weight loss. Diverse patient needs, the demand for ongoing support, and limited resources underscore the potential of using digital support tools. Objective: This study aimed to evaluate the usability, treatment satisfaction, and weight effects of a personalized nutrition advisor (PNA), a prototype decision-support tool designed to facilitate personalized weight management counseling. Methods: We assessed usability, treatment satisfaction, and weight effects of a web-based PNA prototype dashboard designed to help dietitians deliver personalized remote dietary counseling in overweight adults (BMI ≥28 kg/m² at pharmacotherapy initiation) who had achieved ≥5% weight loss with GLP-1 RA therapy over 12-weeks. The PNA dashboard generated tailored nutritional recommendations to help participants achieve personalized weight loss goals based on an energy balance model that estimated daily caloric intake and nutritional quality using frequent body weight measurements, dietary logs, and physical activity data from a lifestyle-tracking app. To evaluate the PNA's usability, we used a convergent parallel mixed-methods approach, combining a validated quantitative usability survey and qualitative focus-group interviews and feedback questionnaires with both dietitians and patients, alongside patient-reported satisfaction metrics for PNA-guided consultations (treatment satisfaction, general self-efficacy, and perceived health impact). Thematic analysis with a hybrid deductive-inductive methodology was applied to qualitative data, using 4 a priori themes derived from this study's conceptual framework regarding prior expectations, perceived utility and satisfaction, usability challenges, and suggestions for clinical integration. Percent weight loss during the intervention was assessed as an exploratory outcome. Results: Among 78 participants (58/78, 74% women), on GLP-1 RA (mean weight loss of -13.3%, SD 6.7%, after 10, SD 5, months of treatment), between 3 and 5 remote nutrition consultations were delivered with PNA support. After the 3-month intervention period, weight loss was sustained in all participants (-0.2%, SD 2.5%), with 21% (16/78) suspending the GLP-1 RA due to drug shortages. Dietitians rated the PNA's usability as moderate (62%) on the Healthcare Systems Usability Scale. Patients evaluated the perceived health impact of the PNA-assisted consultations at 19.1 (SD 3.5) of 25 on the user version of the Mobile Application Rating Scale. No significant differences were observed in patient-reported treatment satisfaction (P=.78) or self-efficacy (P=.57) before and after PNA-assisted care. Qualitative analysis identified convergence with quantitative findings across themes of usability, treatment satisfaction, and clinical integration, with divergence observed for self-efficacy and tracking motivation. Both patients and dietitians found the PNA valuable for generating actionable nutritional insights. Conclusions: While effective implementation of tools such as the PNA prototype demands dietitian training and workflow integration, they offer scalable, personalized nutrition or lifestyle guidance-as a therapeutic decision-support tool within weight loss interventions, with or without adjunct GLP-1 RA pharmacotherapy.