Assessment of Macrophage Activation syndromE in STill's Disease

Inclusion Criteria

• •Age \>6 months and ≤80 years at the beginning of the index MAS episode.
• •Diagnosis of Still's disease (sJIA (systemic Juvenile Idiopathic Arthritis) or AOSD (Adult Onset Stills Disease) diagnosis).
• •Diagnosis of MAS according to treating physician in the medical record.
• •Patients who have received at least 3 consecutive days of GC after diagnosis of MAS and/or are judged by the Investigator to be refractory to GC due to clinical worsening of patient's condition .
• •The onset of the index MAS episode occurred between 01 January 2012 and 30 September 2022.