Avoidant/restrictive food intake disorder prognosis and its relation with autism spectrum disorder in Japanese children.

Background: There is a lack of reported clinical factors associated with the outcomes of children and adolescents with avoidant/restrictive food intake disorder (ARFID) in Japan. This study aimed to identify these clinical factors and explore the relationship between ARFID and autism spectrum disorder (ASD).

Methods: This retrospective study analyzed data from 48 Japanese children and adolescents with ARFID who visited Okayama University Hospital between January 2011 and March 2022. Clinical characteristics were assessed using medical records and natural history questionnaires. The study compared patients with good and poor prognosis groups and used multiple logistic regression analysis to determine factors influencing prognosis.

Results: The study included 33 patients with good prognoses and 15 with poor prognoses. Comorbid ASD was more prevalent in the poor prognosis group (60%) compared to the good prognosis group (21%). Additionally, more than half of the ARFID patients with comorbid ASD were initially undiagnosed. Multivariate analysis revealed that older age at first visit (p = 0.022) and comorbid ASD (p = 0.022) were statistically significant factors associated with poor prognosis in ARFID patients. There were no significant differences in body mass index standard deviation score and maximal weight loss between the two groups.

Conclusions: The poor prognosis group had a higher prevalence of comorbid ASD diagnoses. Therefore, it is crucial to evaluate patient's developmental characteristics early in treatment and consider these characteristics throughout the course of care.