Abstract Background/Aims Patients who do not achieve sustained low disease activity despite drug treatments are referred to as having refractory disease. However, usage of this term varies and often does not account for any discrepancy between inflammation and persistent symptoms, adult or juvenile onset nor differences between patients’ and healthcare professionals’ perspectives. The study aimed to explore and achieve consensus on a definition of refractory disease across healthcare professionals and patients, through a mixed-methods Delphi approach. Methods Three rounds of voting (one face-to-face nominal group (n = 13), and two online rounds (ns = 40 and 53)) were conducted, in conjunction with the National Rheumatoid Arthritis Society. Participants voted on the inclusion and relevance of statements to generate a broader definition of refractory disease, derived from previous qualitative interviews with multi-disciplinary healthcare professionals and patients (adult and juvenile onset), a systematic review of current definitions and health psychology theory. The process involved voting on: a) name preferences, b) treatment and inflammation statements, c) domains for inclusion regarding symptoms and impact, and d) rating of individual components within each domain, including relevance to: i) Refractory Arthritis and ii) Disease Flare for discriminatory validity. A predetermined cut off was applied to identify which domains needed to be included, until final consensus was reached. Full NHS ethical approval was granted (London-Hampstead-18/LO/1171). Results With minimal attrition (n = 3 in both online rounds), 106 international participants including Patient Representatives, Rheumatologists, Nurses, GPs, Psychologists, Physiotherapists, Researchers, Pharmacist, Podiatrist, Occupational Therapist and a Social Worker participated. Refractory Inflammatory Arthritis was the most popular name, (25% of votes) followed by Persistent Inflammatory Arthritis (19% of votes) hence its application in the presence (Persistent Inflammation) or absence (Persistent Symptoms) of inflammation as part of the definition. Regarding treatment and inflammation, these were voted in the majority to be kept broad rather than specifying rigid cut-offs. From the original 73 components across 10 domains identified to capture symptoms and impact, initial analysis has resulted in six domains reaching consensus for inclusion. These domains cover: 1) Disease Activity, 2) Joint Involvement, 3) Pain, 4) Fatigue, 5) Functioning and Quality of Life, and 6) cs/b/tsDMARD Experiences. Within these, 18 components were identified as related and important e.g. One or two persistently active/affected joints, Reduced mobility, Disease-related Distress, Inability to perform desired activities, Repeated need of short course steroids and Disease Activity not captured by DAS28. These capture the multi-faceted presentation and experience of Refractory Inflammatory Arthritis in these two populations. Conclusion A broader definition for refractory inflammatory arthritis has been generated through a Delphi method to capture the experiences of rheumatologists, patients and multi-disciplinary healthcare professionals. This definition needs further refinement and validation to assess clinical and research utility to identify high risk patients with unmet needs. Disclosure H. Chaplin: None. A. Bosworth: None. J. Meehan: None. R. Moss-Morris: None. H. Lempp: None. S. Norton: None.