Patients with Adult-onset Still’s Disease in Germany: A Retrospective Analysis of Clinical Characteristics and Treatment Practices Ahead of the German Recommendations

Background/Objectives: Adult-onset Still’s disease (AOSD) is an autoinflammatory disorder that can be challenging to diagnose and manage. The goal of this study was to analyze retrospective data to provide insights into the clinical presentation, disease activity, and treatment outcomes of AOSD during routine clinical care. Methods: This retrospective database analysis included adult patients (≥18 years) with a diagnosis of AOSD who had a clinical visit between January 1, 2010, and December 31, 2020. Evaluated outcomes included demographic characteristics, symptoms, disease activity, and treatment. Results: Our study included 120 patients (55.8% female) diagnosed with AOSD at ten German rheumatology centers. The mean (standard deviation [SD]) age was 51 (16) years and the mean (SD) time from diagnosis was 9 (7) years. Approximately half (55.0%) had a polycyclic disease course. The most frequent symptoms at initial diagnosis were arthralgia (87.5%) and fever (71.7%), and these symptoms continued in a substantial proportion of patients at the current visit (29.2% and 18.3%, respectively). High neutrophil and ferritin levels were also common. Mean disease activity scores improved from initial diagnosis to current visit (from 4.66 to 1.97 for the Still Activity Score). The treatments most frequently used at some point in the disease course were glucocorticoids (95.8%), interleukin (IL)-1 inhibitors (74.2%), and methotrexate (70.8%). The most common current treatments were IL-1 inhibitors (45.8%) followed by methotrexate (24.2%) and glucocorticoids (23.3%). Conclusions: Patients with AOSD seen at German rheumatology clinics show strong improvements in symptoms and disease activity from initial diagnosis, but a high burden of disease remains in some patients. Future studies will be needed to document the impact of new guidelines on treatment patterns.