To assess concordance among criteria for inactive disease (ID) and low disease activity (LDA) in juvenile idiopathic arthritis (JIA), and to seek for factors driving discordance. The frequency of fulfillment of existing criteria was evaluated in 10,186 patients extracted from three cross‐sectional datasets. Patients were divided in the “functional phenotypes” of oligoarthritis and polyarthritis. Concordance between criteria was examined through weighted Venn diagrams. The role of each individual component in explaining discordance between criteria was assessed by calculating the absolute number and percentage of instances in which the component was responsible for discrepancy between definitions.

ID criteria were met by 28.6 to 41.1% of patients with oligoarthritis and by 24.0 to 33.4% of patients with polyarthritis. LDA criteria were met by 44.8 to 62.4% of patients with oligoarthritis and by 44.6 to 50.4% of patients with polyarthritis. There was a 57.9 to 62.3% overlap between ID criteria and a 67.9 to 85% overlap between LDA criteria. Parent and physician global assessments and acute phase reactants were responsible for the majority of instances of discordance among ID criteria (8.7‐15.5%, 10.0‐12.3%, and 10.8‐17.3%, respectively).

We found fair concordance between criteria for ID and LDA in JIA, with the main drivers of discordance for ID being physician and parent global assessments, and acute phase reactants. This observation highlights the need for further studies aimed to evaluate the impact on ID definition of physician and parent subjective perception of disease remission and of laboratory measures of inflammatory activity.

Ref: https://onlinelibrary.wiley.com/doi/10.1002/acr.24415

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