The OMERACT core domain set designed to assess the efficacy of medication in randomized controlled trials (RCTs) for juvenile idiopathic arthritis (JIA), originally established in 1997 [1], was re-evaluated and updated in 2018 by the JIA Working Group (https://omeract.org/working-groups/juvenile-idiopathic-arthritis/) to integrate patient and parent/caregiver perspectives into the core domain set. This work culminated in the creation of the OMERACT JIA core domain set recommended for use in RCTs and longitudinal observational studies (LOS). The 2018 established mandatory domains included: pain, joint inflammatory signs, activity limitation/physical function, patient perception of disease (overall well-being), and adverse events including death [2]. After establishing the core domain set, each domain requires a detailed definition and description to serve as the foundation for the instrument selection process and assist in domain matching and content validity as outlined in the OMERACT handbook [3,4].

The JIA Working Group has endeavored to establish potential domain definitions and descriptions for the mandatory core domain of patient perception of disease (overall well-being) through a consensus-based approach with global stakeholders including patients, parents/caregivers, and healthcare providers. This report details the results of this work as presented at the 2023 OMERACT JIA Special Interest Group (SIG) session.