Items identified by expert physicians for the development of the criteria for the assessment of disease activity for adult-onset Still's disease: results of a web-based Delphi study informing the development of the European Alliance of Associations for Rheumatology (EULAR) criteria for the assessment of disease activity in these patients.

Objectives: The assessment of activity in adult-onset Still's disease (AOSD) remains difficult because of no validated score for this disease. A task force commissioned by the European Alliance of Associations for Rheumatology (EULAR) undertook a 3-round consensus-building study to elicit items to be included in the criteria for the assessment of disease activity for AOSD. Methods: Candidate items were initially extracted from a systematic literature review, and additional items were collected from expert physicians' answers to open-ended questions during the first Delphi round via a web-based application. In the second round, the expert physicians scored items for relevance. Subsequently, the expert physicians were presented the results of the group ratings and asked to score again in the third and final Delphi round. The cutoff for including an item in the criteria for the assessment of disease activity was set at ≥75% for the top 2 ratings ('absolutely required' and 'important'). Results: In total, 25 expert physicians from 7 countries participated in all 3 Delphi rounds. A total of 28 candidate items were initially identified. In the final expert rating, the 14 following items were above the cutoff: fever, cutaneous rash, arthralgia, arthritis, splenomegaly, lymphadenopathies, pleuritis, pericarditis, white blood cell count ≥10,000/mm Conclusions: The study is the first part of the development and validation of the criteria for the assessment of disease activity in AOSD.