A retrospective study on 158 Thai patients with juvenile idiopathic arthritis followed in a single center over a 15-year period

Aim: To determine the outcomes of juvenile idiopathic arthritis (JIA) in Thai children. Methods: A retrospective cohort study. All JIA patients in a rheumatology clinic, Ramathibodi Hospital, between July 1997 and December 2012 were enrolled. The patient data were reviewed from medical records. At the most recent follow-up visit, patient outcomes were assessed in three aspects: disease status, functional outcomes and structural damage. Results: Of 168 patients, 158 (94.0%) were assessed in disease status and functional outcomes, with 114 patients (67.9%) assessed in three aspects over 4years of disease. The most common JIA category was systemic JIA (SJIA) (33.8%), followed by enthesitis-related arthritis (ERA) (24.8%), oligoarthritis (18.5%), rheumatoid factor (RF)-negative polyarthritis (15.3%), RF-positive polyarthritis (7.6%) and one undifferentiated arthritis. SJIA had the highest remission rate due to early diagnosis and prompt treatment compared to other categories, whereas RF-positive polyarthritis carried the worst prognosis in three aspects, followed by ERA. Moreover, ERA patients had the highest failure rate in conventional therapy, half of whom had combined treatment with biologic agents and presence of human leukocyte antigen (HLA)-B27 was a predictor for biologic treatment in ERA patients. In addition, disease duration > 2years or failure of conventional therapy was a predictor of structural bone damage. Conclusions: SJIA had the highest remission rate, whereas RF-positive polyarthritis had the worst outcome in three aspects. Prolonged disease duration or failure of conventional therapy was a predictor of structural bone damage, while HLA-B27 was a predictor for biologic treatment in ERA patients.