POS0172 WORLDWIDE EVALUATION OF CLINICAL PRACTICE STRATEGIES (CliPS) FOR LUNG DISEASE IN STILL’S DISEASE WITHIN THE JIR-CliPS NETWORK: A COST ACTION

Background: Increased understanding of pathophysiological mechanisms now confirms that systemic juvenile arthritis (sJIA) and adult-onset Still's disease (AOSD) represent a single clinical entity, differentiated only by age of onset - below or above 16 years. Recent literature has documented a subset of pediatric patients with severe clinical presentations (recurrent macrophage activation syndromes (MAS), reactions to biologics, early disease onset before 2 years of age) who are prone to develop lung disease (LD) [1]. Despite previous observations of interstitial LD in patients with adult-onset Still's disease [2], the underlying mechanisms remain poorly understood. Due to the rarity of this clinical manifestation, management relies on recommendations derived from clinical expertise based on a limited number of cases [3]. Objectives: To elucidate the knowledge and clinical practice strategies of physicians worldwide regarding LD in Still's disease, with the aim of highlighting the challenges associated with this clinical entity and to compare these observations with expert recommendations (EULAR). Methods: This study is part of the CLiPS project, a work dedicated to capture clinical practice strategies worldwide by disseminating questionnaires to physicians about five diseases, including Still's disease. The project, funded as a COST (European Cooperation for Science and Technology) action, has been distributing the questionnaires since September 2022 through the JIRcohort network and national societies. Results: On 286 physicians responding to the sJIA/AOSD questionnaire, 43 physicians (15%) from 17 countries reported following Still's disease patients with LD. Most respondents were pediatricians (70%), 17% cared for both adults and children, and 5 were adult physicians. Some physicians treated between 10 and 30 patients, but most followed one or two patients. A first survey aimed to describe LD in Still's disease. Sixty-three percent of the physicians reported non-specific respiratory symptoms (dry cough, dyspnea, tachypnea). When analyzing these responses, it became unclear whether some doctors were considering infectious or inflammatory complications. We decided to exclude inaccurate responses. The analysis therefore focused on 22 physicians who answered this question accurately, from 10 different countries. Acute digital clubbing, a history of recurrent MAS and adverse events to biotherapies were identified as key clinical features to differentiate LD. In terms of diagnostic tools, chest radiography was universally performed, supplemented by CT scan in 72% of responders. HLADRB1*15 was used by 53% of physicians to support LD, while 38% never requested this test. In terms of therapeutic approaches, fifty percent of respondents chose to stop ongoing biologics while 50% opted to continue. Fifty nine percent of participants added JAK inhibitors, either alone or in combination with mycophenolate mofetil or cyclosporine. Twenty-seven percent chose cyclosporine or mycophenolate mofetil to treat LD. Conclusion: This study highlights the challenges of diagnosing and managing the manifestation of lung involvement in Still's disease. Both adult and pediatric physicians worldwide deal with patients with LD, and additional expert consultation is needed to optimize this comprehensive review. In the absence of cohort studies, expert recommendations are essential to raise awareness of the diagnosis and guide management. REFERENCES: [1] Schulert, G. S. and al. (2019). Systemic Juvenile Idiopathic Arthritis–Associated Lung Disease: Characterization and Risk Factors. Arthritis & Rheumatology. [2] Takakuwa, Y. and al. (2019). Adult-onset Still's disease-associated interstitial lung disease represents severe phenotype of the disease with higher rate of haemophagocytic syndrome and relapse. Clinical and Experimental Rheumatology. [3] Towe, C. and al. (2023). Diagnosis and Management of the Systemic Juvenile Idiopathic Arthritis Patient with Emerging Lung Disease. Pediatric Drugs, 25(6), 649-658. Acknowledgements: NIL. Disclosure of Interests: None declared.