Inflammatory Arthritis and Difficulty at Work

The development of the patient-reported outcome (PRO) measure will comprise: Step 1: Identifying themes and generating items by * Conducting focus groups and/or individual semi-structured interviews with patients with IA to identify the problems faced at work due to the disease and identify strategies helpful for maintaining employment. Work characteristics, work environment, and social, economic factors and role of family members will receive specific attention. * Conducting focus groups including patients with IA who stay at work despite the disease to identify their motivations and needs to stay at work. * Conducting individual semi-structured interviews with health care professionals and professionals of the prevention and security at work * Conducting the thematic analysis, following a general inductive approach Step 2: Selecting items using a Delphi method using a panel of patients and health care professionals Step 3: Items reconciliation and selection by an expert panel Step 4: Cognitive debriefing of selected items (pre-test). Step 5: Evaluate psychometric properties will follow the standards for assessing validity of a complex measurement scale, checking for truth, discrimination and feasibility ((Outcome Measures in Rheumatology (OMERACT) filter 2.0) according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) check-list. Scale measurement properties will be assessed using Rasch measurement methods.