Bridging the gap between 2024 EULAR/PreS Recommendations for Still's Disease and practice: the need for awareness of biomarkers and timely use of IL-1/ IL-6 inhibition.

Introduction: Still's Disease (SD), encompassing both systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) is a rare condition, therefore posing unique challenges in diagnosis and management, which can lead to delayed treatment and increased morbidity. The current state of practice regarding SD management varies widely across different countries. Very recently, a EULAR/PReS taskforce published new recommendations for the diagnosis and management of SD, providing tools to accelerate its diagnosis, including new biomarkers such as IL-18 and S100 proteins and recommending early initiation of IL-1 or IL-6 inhibition to avoid prolonged systemic glucocorticoid exposure.

Methods: Cross-sectional, descriptive, and observational study utilizing a structured questionnaire to collect data from healthcare professionals involved in the diagnosis and treatment of SD in Portugal.

Results: We obtained 52 responses from Portuguese clinicians. Only 10% use IL-18 levels and 25% use S100 proteins to aid in the diagnosis of SD. Half of the responders expect to achieve clinically inactive disease (CID) with low-dose glucocorticoids after 3 months, but only 39% aim to achieve CID without glucocorticoids at month 6. For 95% of responders the use of glucocorticoids is part of the first line of therapy. Less than half (37%) did not include IL-1 or IL-6 inhibitors in their first line of treatment.

Conclusion: The results of the questionnaire applied show that there is still a gap between clinical practice and the recent recommendations, as demonstrated by the underuse of recent biomarkers and biologic therapies, which should be bridged in order to improve health outcomes for individuals affected by SD.