Comparison between continued inpatient treatment versus day patient treatment after short inpatient care in early onset anorexia nervosa (COTIDEA trial): a study protocol for a non-inferiority randomised controlled trial.

Background: In children with early-onset anorexia nervosa (first symptoms before 13 years old, EO-AN), experts recommend initial outpatient treatment but in-patient treatment (IP) is frequently indicated due to acute medical instability or for those who have not improved with outpatient treatment. This IP can target either a partial weight restauration or a total weight normalization (return to the previous BMI growth trajectory). There are no evidence in the literature on which is the better therapeutic option in EOAN. But as long length of stay induce social isolation, with elevated costs, we wonder if a stepped-care model of daypatient treatment (DP) after short IP stabilisation may be a treatment option as effective as full-time IP to target weight normalization. We designed a two-arm randomised controlled trial testing the non-inferiority of a stepped-care model of DP after short IP stabilisation versus full-time IP.

Methods: Eighty-eight children aged 8 to 13 years suffering from EOAN with initial severe undernutrition will be randomly allocated to either IP treatment as usual or a stepped care DP model both targeting weight normalization. Assessments will be conducted at inclusion, somatic stabilization, weight normalization, 6 months and 12 months post randomisation. The primary outcome will be BMI at 12 months post-randomisation. Secondaries outcomes will included clinical (tanner stage), biological (prealbumin, leptin, total ghrelin and IGF1) and radiological (bone mineralization and maturation) outcomes, eating symptomatology and psychiatric assessments, motivation to change, treatment acceptability and quality of life assessments, cost-utility and cost-effectiveness analyses.

Discussion: COTIDEA will provide rigorous evaluation of treatment alternative to full-time inpatient treatment to allow a reduction of social iatrogenic link to hospital length of stay and associated costs.

Trial Registration: Trial is registered on ClinicalTrials.gov (NCT04479683).