Chronic arthritis and carpo : metacarpal ratio in Japanese patients with adult Still's disease

Objective. To characterize Japanese patients having adult Still's disease ( ASD) with chronic arthritis (> 6 months) and to examine the association of chronic arthritis with carpo:metacarpal ratio (CMC ratio), an index of radi ographic progression in rheumatoid arthritis (RA), Methods. Twenty-seven patients with ASD (16 women and 11 men, mean age at d isease onset 27.7 years) were classified into 2 groups: patients with (chro nic articular ASD, 16 patients, 59%) or without (systemic ASD, 11 patients, 41%) chronic arthritis. Clinical and laboratory findings were compared bet ween both groups. CMC ratio was calculated on serial hand radiographs in pa tients with chronic articular ASD. Results, In our series, serositis was rarely observed in chronic articular ASD, Peripheral arthritis (including transient arthritis), such as metacarp ophalangeal, proximal interphalangeal, or ankle joint, was more frequently observed in chronic articular ASD than in systemic ASD (p < 0.05). Wrist ar thritis was frequently observed also in systemic ASD; however, joint space narrowing of carpometacarpal or intercarpal joints was recognized only in c hronic articular ASD (44%). CMC ratio at the last observation in 14 patient s with chronic articular ASD was significantly decreased (0.526 +/- 0.039) compared to that at disease onset (0.553 +/- 0.034) (p < 0.05), while no de crease was observed in 4 with systemic ASD (0.565 +/- 0.062 at disease onse t, 0.563 +/- 0.043 at the last observation). Conclusion. It is suggested that chronic articular ASD has certain characte ristics. CMC ratio may be a quantitative index for assessment of radiograph ic changes of carpal joints, not only in RA but also in chronic articular A SD.