Objective. To describe the disease characteristics, long-term course, and outcome of patients with juvenile idiopathic arthritis (JIA) in a population-based setting.Methods. Consecutive cases of JIA from defined geographic areas of Denmark, Finland, Sweden, and Norway in whom disease onset occurred in 1997-2000 were included in a prospective, multicenter cohort study. The study was designed to be as close to a population-based study as possible, with centers participating only if they were able to include in their catchment area all children in whom JIA was diagnosed.Results. Of 500 children included, 440 (88.0%) had repeated visits, with the last visit occurring at least 7 years after disease onset (median 98 months, range 84-147 months). Changes in the International League of Associations for Rheumatology category were observed in 10.8% of the children, and, in addition, extended oligoarthritis developed in 34.7% of the group with oligoarticular JIA. During the observation period, 58.0% of the children were treated with diseasemodifying antirheumatic drugs, including biologic medications. Ongoing disease activity was mostly mild, but some JIA-related damage developed in 22.9% of the children. At the last followup visit, remission off medication was observed in 42.4% of the children, 8.9% were in remission on medication, and 48.7% were not in remission. The highest rates of remission were observed in patients with persistent oligoarticular JIA and in those with systemic JIA.Conclusion. In this long-term prospective study of JIA in a population-based Nordic setting, ongoing disease was evident in a majority of the children. The present results underline the need to identify early predictors of outcome, to further improve therapy, and to continue long-term followup of patients with JIA.

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Objective The present study was undertaken to assess the long‐term course, remission rate, and disease burden in juvenile idiopathic arthritis (JIA) 18 years after disease onset in a population‐based setting from the early biologic era. Methods A total of 510 consecutive cases of JIA with disease onset between 1997 and 2000 from defined geographic regions in Denmark, Norway, Sweden, and Finland were prospectively included in this 18‐year cohort study. At the follow‐up visit, patient‐reported demographic and clinical data were collected. Results The study included 434 (85%) of the 510 eligible JIA participants. The mean ± SD age was 24.0 ± 4.4 years. The median juvenile arthritis disease activity score in 71 joints (JADAS‐71) was 1.5 (interquartile range [IQR] 0–5), with the enthesitis‐related arthritis (ERA) category of JIA having the highest median score (4.5 [IQR 1.5–8.5], P = 0.003). In this cohort, 46% of patients still had active disease, and 66 (15%) were treated with synthetic disease‐modifying antirheumatic drugs and 84 (19%) with biologics. Inactive disease indicated by a JADAS‐71 score of <1 was seen in 48% of participants. Clinical remission off medication (CR) was documented in 33% of the participants with high variability among the JIA categories. CR was most often seen in persistent oligoarticular and systemic arthritis and least often in ERA (P < 0.001). Conclusion A substantial proportion of the JIA cohort did not achieve CR despite new treatment options during the study period. The ERA category showed the worst outcomes, and in general there is still a high burden of disease in adulthood for JIA.

BackgroundThe incidence of uveitis associated with juvenile idiopathic arthritis (JIA) varies around the world. Our aim was to investigate the incidence and predictors of uveitis in a Nordic population-based cohort.MethodsConsecutive JIA cases from defined geographical areas in Denmark, Finland, Sweden and Norway with disease onset between January 1997 to June 2000 were followed for median 98 months in this prospective longitudinal cohort study. Potential clinical and immunological predictors of uveitis were identified with logistic regression analysis.ResultsUveitis occurred in 89 (20.5%) of the 435 children with regular ophtalmologic follow-up among the 500 included. Chronic asymptomatic uveitis developed in 80 and acute symptomatic uveitis in 9 children. Uveitis developed at a median interval of 0.8 (range − 4.7 to 9.4) years after onset of arthritis. Predictors of uveitis were age < 7 years at JIA onset (Odds ratio (OR) 2.1, 95% confidence interval (CI) 1.3 to 3.5), presence of antihistone antibodies (AHA) > 15 U/ml (OR 4.8 (1.8 to 13.4)) and antinuclear antibodies (ANA) (OR 2.4 (1.5 to 4.0)). Mean combined IgM/IgG AHA was significantly higher in the uveitis group (19.2 U/ml) than in the non-uveitis group (10.2 U/ml) (p = 0.002). Young age at JIA onset predicted uveitis in girls (p < 0.001), but not in boys (p = 0.390).ConclusionEarly-onset arthritis and presence of AHA in girls, as well as presence of ANA in both genders, were significant predictors of chronic uveitis. The high incidence of uveitis in this long-term Nordic JIA cohort may have severe implications in a lifelong perspective.

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