Achievement and Usefulness of Intermediate Treatment Targets for Still Disease Proposed by the European Alliance of Associations for Rheumatology and the Paediatric Rheumatology European Society.

Objective: Intermediate treatment targets in Still disease have been proposed by the European Alliance of Associations for Rheumatology (EULAR) and the Paediatric Rheumatology European Society (PReS) in 2024. This study aimed to evaluate the utility of the targets in clinical practice.

Methods: Consecutive patients with adult-onset Still disease (AOSD) based on the Yamaguchi criteria who visited Keio University Hospital from April 2012 until May 2024 were retrospectively reviewed. We assessed the achievement rates of the following treatment targets: day 7 (resolution of fever and reduction of C-reactive protein [CRP] by > 50%); week 4 (no fever, reduction of active joint count by > 50%, and normal CRP); month 3 (clinically inactive disease [CID] with < 0.1 mg/kg/day of glucocorticoids [GCs]); and month 6 (CID without GCs). We also assessed the association of treatment target achievement with long-term outcomes including recurrence and discontinuation of GCs.

Results: Sixty-two patients were included in the analysis. The mean age was 50.8 (SD 19.5) years, and 47 (75.8%) were female. The recommended treatment targets were achieved in 67.2% at day 7, 61.1% at week 4, 3.3% at month 3, and 1.7% at month 6. Failure to achieve targets at months 3 and 6 was mainly because of GC usage. During the median observational period of 7.1 years, patients who achieved CID at month 6 had fewer recurrences thereafter (hazard ratio [HR] 0.27, 95% CI 0.11-0.68). Successful GC withdrawal was associated with CID at month 3 and the use of biologic agents at month 6 (HR 2.51, 95% CI 1.15-5.46 and HR 2.29, 95% CI 1.14-4.61, respectively).

Conclusion: The EULAR/PReS intermediate treatment targets for Still disease are useful in the clinical management of AOSD.