Objectives Avoidant/Restrictive Food Intake Disorder (ARFID) is characterised by a persistent disturbance in feeding or eating which results in an inability to meet nutritional and/or energy needs and leads to at least one of the following: weight loss; nutritional deficiency; dependence on enteral feeding or nutritional supplements; or significant interference with psychosocial functioning. There have been limited large scale epidemiological studies on ARFID. One national surveillance study from Canada reported the incidence of ARFID in children and adolescents presenting to paediatricians to be 2.02 per 100,000 patients. This study aims to examine the incidence and clinical characteristics of ARFID in children and adolescents in the United Kingdom (UK) and Republic of Ireland (ROI).

Methods This study was conducted using the British Paediatric Surveillance Unit (BPSU) and the Child and Adolescent Psychiatry Surveillance System (CAPSS). Paediatricians reported monthly those children and adolescents aged 5 to 15 years seen with a new diagnosis of ARFID using a broad definition. Child and adolescent psychiatrists reported children and adolescents aged 5 to 17 years using the same definition.

Results Between 1st March 2021 and 31st March 2022 paediatricians reported 569 cases and child and adolescent psychiatrists reported 348. Of those, 289 cases of ARFID were eligible for inclusion using a narrower analytic definition. 33 additional cases were included from clinicians that did not report to the BPSU or the CAPSS. A total of 322 cases were included (mean [SD] age, 11.20 [3.77]; 148 [45.96%] female; 242 [84.03%] white ethnicity). The minimum incidence of ARFID in the UK and ROI was 3.09 (95% CI, 2.77–3.45) per 100,000 young people aged 5 to 17 years. The mean (SD) BMI z-score was -1.29 (1.80). The most common comorbidities were anxiety disorders (53.8%) and autism spectrum disorder (43.17%). Dietetic advice was the most common clinical management offered (76.4%).

Conclusions This constitutes the largest study on ARFID so far in the UK and Ireland and suggests that ARFID is not an uncommon disorder in children and adolescents. The range of presentations included within the diagnosis leads to multiple potential pathways into clinical care. These data will inform service development for this patient group, and will allow to make international comparisons.