1 Sainte-Justine University Hospital Research Center, Montreal, QC, Canada.
2 Department of Psychiatry and Addictology, Université de Montréal, Montreal, QC, Canada.
3 Department of Psychology, Concordia University, Montreal, QC, Canada.
4 Department of Psychology, Sainte-Justine University Hospital Centre, Montreal, QC, Canada.
5 Department of Psychiatry, McGill University, Montreal, QC, Canada.
6 Division of Adolescent Medicine, Department of Pediatrics, Sainte-Justine University Hospital Centre, Université de Montréal, Montreal, QC, Canada.

Background: The incidence of eating disorders (EDs) among adolescents has significantly increased since the beginning of the COVID-19 pandemic. Hybrid care, which combines web-based and in-person modalities, is a promising approach for adolescents with EDs but remains understudied in this population.

Objective: We aimed to implement a novel hybrid (web-based and in-person) intensive ambulatory care program for youth and evaluate its feasibility, acceptability, and preliminary effectiveness.

Methods: We will use a naturalistic pretest-posttest design to evaluate our proposed pilot Intensive Ambulatory Care Program (IACP). This novel type of day hospital care follows evidence-based principles and uses a family-centered, educational, and motivational approach. It will be tailored to the psychological needs of each participant and will be delivered in a hybrid format. A total of 100 participants meeting the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) criteria for EDs, aged 12-18 years, will be recruited over the 2-year trial period. We will examine recruitment, retention, and adhesion-to-protocol rates; participant and family satisfaction; and preliminary effectiveness using quantitative self-report questionnaires.

Results: Rolling recruitment will take place from winter 2022 to fall 2023, during which time we expect to recruit approximately 80% (100/120) of eligible participants, retain at least 75% (75/100) of enrolled participants and have at least 70% (70/100) of enrolled participants complete at least one therapeutic session per week and all pre- and postintervention questionnaires. Data collection will occur concurrently. We base our recruitment and retention estimates on previous literature and consider that the highly flexible design of the IACP and the fact that no extra work will be required of individuals in the program to participate in the study, will lead to high levels of feasibility. We anticipate that participants and their families will be satisfied with both the program and hybrid delivery format. We expect that participation in the IACP will be associated with a medium effect size reduction in ED psychopathology from baseline to end of treatment. The data analysis and manuscript writing are expected to be completed by the summer of 2024.

Conclusions: Given the high clinical burden associated with EDs, this study has the potential to fill an important research gap by testing the implementation of a novel hybrid mode of intervention. If feasible, acceptable, and effective, the IACP could lead to important improvements in health care services for adolescents with EDs.

International registered report identifier (irrid): PRR1-10.2196/37420.