ARTHRITIS & RHEUMATISM Vol. 54, No. 5, May 2006, pp 1595–1601 DOI 10.1002/art.21774 © 2006, American College of Rheumatology Predictors of Disease Course and Remission in Systemic Juvenile Idiopathic Arthritis Significance of Early Clinical and Laboratory Features D. Singh-Grewal, R. Schneider, N. Bayer, and B. M. Feldman Objective. To determine whether the disease course in systemic juvenile idiopathic arthritis (JIA) can be characterized as monophasic, polycyclic, or per- sistent, and to determine whether early clinical and laboratory characteristics can be used to predict the disease course and time to remission. Methods. Forty-five children with systemic JIA diagnosed between 1996 and 2000 were followed up with a standardized data collection protocol, including data on clinical and laboratory features (mean followup 4.9 years). Disease was considered inactive if the clinical and laboratory features were normal. Three definitions of remission were applied to classify disease course. Predictors of disease course were evaluated using mul- tiple logistic regression. Predictors of time to remission were evaluated using Cox proportional hazards regres- sion. Results. When applying a definition of remission requiring inactive disease while not receiving any med- ications for a period of 3 months, 42.2%, 6.7%, and 51.1% of the patients were classified as having monophasic, polycyclic, and persistent disease, respec- tively. Fever and active arthritis at 3 months (R 2  0.42, area under the receiver operating characteristics curve [AUC]  0.76) and an erythrocyte sedimentation rate (ESR) >26 mm/hour and corticosteroid use at 6 months (R 2  0.49, AUC  0.92) were predictive of a non- monophasic course. Absence of active arthritis, an ESR of <26 mm/hour, and no requirement for corticosteroid therapy at 3 and 6 months were predictors of an earlier time to remission. Conclusion. The disease course in systemic JIA can be characterized as monophasic, polycyclic, or per- sistent using a definition of remission requiring 3 months of inactive disease while not receiving any therapy. Features at 3 and 6 months are predictive of the disease course and time to remission. Systemic juvenile idiopathic arthritis (JIA) is a chronic disease that results in significant morbidity and mortality in children. Approximately 10% of children with JIA have the systemic form (1). Children with systemic JIA are known to develop chronic disability and significant functional impairment (2–8). Packham and Hall (3) found that after almost 30 years of followup, 75% of patients with systemic JIA had undergone joint replacement, and almost two-thirds were classified as having Steinbrocker stage III or IV disease and had Health Assessment Questionnaire scores in the severe disability range (9,10). Bowyer and colleagues (2) showed that after 5 years of followup, 18% of children with systemic JIA were growth impaired and 75% had radiographic evidence of joint space narrowing. Few studies have adequately evaluated the dis- ease course in systemic JIA; however, the labels monophasic, polycyclic, and persistent are frequently used to describe the course of the disease. Lomater et al (11), in a retrospective review of 80 patients, found that 11% had a monophasic disease course, 34% had poly- cyclic disease, and 55% had persistent disease. Fantini et al (12), in a retrospective study of 88 patients, found a very low rate of polycyclic disease (only 2.3% of pa- Dr. Feldman holds the Canada Research Chair in childhood arthritis. D. Singh-Grewal, MBBS, FRACP, R. Schneider, MBBCh, FRCPC, N. Bayer, MD, FRCPC, B. M. Feldman, MD, MSc, FRCPC: The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada. Address correspondence and reprint requests to R. Schnei- der, MBBCh, FRCPC, Division of Rheumatology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G1X8, Canada. E-mail: rayfel.schneider@sickkids.ca. Submitted for publication August 29, 2005; accepted in revised form January 19, 2006. 1595