Identifying eating disorders at the earliest opportunity: Testing the reliability of an online eating disorder screener (IOI-S) in primary care and youth mental health settings.

Aim: Eating disorders (EDs) are associated with significant disease burden and unacceptably high mortality rates. Early intervention significantly improves prognosis and can prevent chronic suffering; however, large numbers of people with the illness are not being identified or managed in primary healthcare. The current study aimed to test the reliability of the face-to-face, clinician delivery of a previously validated, co-designed, online screening tool for eating disorders.

Methods: Individuals aged 14 and over who read, English were recruited from the community in either primary care (general practice) settings or headspace youth mental health centres. They completed the InsideOut Institute Screener (IOI-S) face-to-face, delivered verbally by the study researcher clinician and then online by self-report. The primary outcome was test-retest reliability as measured by two-way mixed effects model Intraclass Correlation Coefficient (ICC) with absolute agreement.

Results: A total of 83 participants aged 14-81 (M 36.2) completed the study in New South Wales and the Northern Territory, Australia, between April and November 2022. The ICC between successive iterations of the test was significantly positive (0.980), demonstrating strong internal validity and test-retest reliability of the scale.

Conclusions: The IOI-S is an adaptive 6-item screening tool designed to 'start a conversation' and determine risk using gentle language conceived by individuals with lived experience. Originally designed for online use, the current study broadens its versatility to clinical settings. The screener performs equally well when delivered face-to-face in clinical practice. In conjunction with increased practitioner education and improved treatment referral pathways, broad implementation of the screener in early healthcare settings can support timely identification and intervention for those with EDs.