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 aim was to develop prediction rules that may guide early treatment decisions based on baseline clinical predictors of long-term unfavorable outcome in juvenile idiopathic arthritis (JIA).MethodsIn the Nordic JIA cohort, we assessed baseline disease characteristics as predictors of the following outcomes 8 years after disease onset. Non-achievement of remission off medication according to the preliminary Wallace criteria, functional disability assessed by Childhood Health Assessment Questionnaire (CHAQ) and Physical Summary Score (PhS) of the Child Health Questionnaire, and articular damage assessed by the Juvenile Arthritis Damage Index-Articular (JADI-A). Multivariable models were constructed, and cross-validations were performed by repeated partitioning of the cohort into training sets for developing prediction models and validation sets to test predictive ability.ResultsThe total cohort constituted 423 children. Remission status was available in 410 children: 244 (59.5%) of these did not achieve remission off medication at the final study visit. Functional disability was present in 111/340 (32.7%) children assessed by CHAQ and 40/199 (20.1%) by PhS, and joint damage was found in 29/216 (13.4%). Model performance was acceptable for making predictions of long-term outcome. In validation sets, the area under the curves (AUCs) in the receiver operating characteristic (ROC) curves were 0.78 (IQR 0.72–0.82) for non-achievement of remission off medication, 0.73 (IQR 0.67–0.76) for functional disability assessed by CHAQ, 0.74 (IQR 0.65–0.80) for functional disability assessed by PhS, and 0.73 (IQR 0.63–0.76) for joint damage using JADI-A.ConclusionThe feasibility of making long-term predictions of JIA outcome based on early clinical assessment is demonstrated. The prediction models have acceptable precision and require only readily available baseline variables. Further testing in other cohorts is warranted.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1571-6) contains supplementary material, which is available to authorized users.

Objective.To determine the prevalence of orofacial symptoms, dysfunctions, and deformities of the temporomandibular joint (TMJ) in juvenile idiopathic arthritis (JIA) 17 years after disease onset.Methods.Drawn from a prospective, population-based Nordic JIA cohort with disease onset from 1997 to 2000, 420 consecutive cases were eligible for orofacial evaluation of TMJ involvement. The followup visit included demographic data, a standardized clinical orofacial examination, and full-face cone-beam computed tomography (CBCT). For comparison, 200 age-matched healthy controls were used.Results.Of 420 eligible participants with JIA, 265 (63%) were included (mean age 23.5 ± 4.2 yrs) and completed a standardized clinical orofacial examination. Of these, 245 had a full-face CBCT performed. At least 1 orofacial symptom was reported by 33%. Compared to controls, the JIA group significantly more often reported TMJ pain, TMJ morning stiffness, and limitation on chewing. Further, among participants reporting complaints, the number of symptoms was also higher in JIA. The mean maximal incisal opening was lower in the JIA group (p < 0.001), and TMJ pain on palpation was more frequent. Condylar deformities and/or erosions were observed in 61% as assessed by CBCT, showing bilateral changes in about 70%. Risk factors of condylar deformities were orofacial dysfunction or biologic treatment; enthesitis-related arthritis was protective.Conclusion.This study of the longterm consequences of TMJ involvement in a population-based JIA cohort reports persistence of comprehensive symptoms, dysfunctions, and damage of the TMJ into adulthood. We suggest interdisciplinary followup of JIA patients also in adulthood.