Clinical Characteristics of Japanese Patients with Elderly-Onset Adult-Onset Still's Disease

The aim of this study was to compare the characteristics of Japanese patients with elderly-onset Adult-onset Still's disease (AOSD) and those with younger-onset AOSD. Patients were classified into elderly-onset (>= 65 years, n = 20) and younger-onset (< 65 years, n = 62) groups according to age at AOSD diagnosis. Analyses included the comparison of clinical features, treatments, and Pouchot and modified Pouchot (mPouchot) scores between the two groups. The frequencies of sore throat, lymphadenopathy, and splenomegaly were significantly lower in the elderly-onset group than in the younger-onset group (30.5% vs. 80.6%, p = 0.0004; 15.0% vs. 54.8%, p = 0.0019; 30.0% vs. 61.3%, p = 0.0203; respectively). There were no significant differences in the frequencies of complications, such as macrophage activation syndrome and disseminated intravenous coagulation, between the patients with elderly-onset or youngeronset AOSD. Serum ferritin levels were higher in the elderly-onset group than in the younger-onset group, albeit without statistical significance (median, 9,423 vs. 4,164 ng/mL, p = 0.1727). Pouchot score was lower in the elderly-onset group than in the younger- onset group (median score, 5.5 vs. 4.0, p = 0.0008); however, there was no significant difference in the mPouchot score between the two groups. Our analyses revealed that elderly-onset AOSD was associated with certain characteristics that were distinct from those of younger-onset AOSD and that the disease severity in patients with elderly-onset AOSD, determined by Pouchot score at the time of AOSD diagnosis, was similar to or less than that in patients with younger-onset AOSD.