Background Reaching inactive disease is the main target of therapeutic interventions in juvenile idiopathic arthritis (JIA). Furthermore, attaining a period of inactive disease early in the disease course has been shown to be predictive for the clinical course in the following years. ICON is a prospective longitudinal observation study carried out at 11 paediatric rheumatology centers in Germany where patients with a diagnosis of JIA (<12 months) have been included.
Objectives To assess how many patients attain a state of clinically inactive disease during the first 12 months of paediatric rheumatology care, and to determine the percentage of time they spent with inactive disease during that time.
Methods We analysed data of ICON patients who had completed the baseline and 12-month assessment. Inactive disease was defined according to the criteria by Wallace et al., i.e. absence of active arthritis, fever, exanthema, generalized lymphadenopathy, splenomegaly, serositis, active uveitis; normal ESR and physician's rating of disease activity ≤0.5 (on a 21-point numeric rating scale from 0-10). Survival analysis was applied to calculate the cumulative time the patients spent with inactive disease during the first 12 months after enrollment.
Results The analysis considered 488 patients (65% female) with a median age of 6 years at baseline and a median disease duration of 6 months. The population had oligoarthritis (52%), followed by polyarthritis (27%), enthesitis-related arthritis (10%), psoriatic arthritis (5%), and systemic arthritis (3%). Diagnosis of JIA was made two months (median) before baseline. About 3/4 of all JIA patients ever reached a state of inactive disease during the first year of observation with a median time from diagnosis to inactive disease of 8 months (IQR 4 – 11). Patients with systemic JIA reached a period of inactive disease in 93%, whereas patients with enthesitis-related arthritis reached this goal in only 52%. The percentage of time with inactive disease was 36% (mean, SD 34%) in all JIA patients during the first 12 months after enrollment, ranging from 20% (mean, SD 29%) in patients with enthesitis-related arthritis to 45% (mean, SD 30%) in patients with systemic arthritis. At the 12-month follow-up, 260 (53%) patients had an inactive disease of whom 102 (21%) were in remission on medication.
Conclusions Under current treatment conditions, the majority of JIA patients reach a state of inactive disease during the first year of paediatric rheumatology care. Significant differences exist between the JIA categories not only in ever reaching a period of inactive disease, but also in the percentage of time the patients spent with inactive disease. Further analysis will show whether attaining inactive disease early in the disease course has an impact on patients' long-term outcomes in this cohort.
Disclosure of Interest C. Sengler: None declared, M. Niewerth: None declared, J. Klotsche: None declared, I. Liedmann: None declared, H.-I. Huppertz: None declared, D. Foell: None declared, G. Horneff Grant/research support: AbbVie, Pfizer, Chugai-Roche, I. Foeldvari: None declared, K. Minden Grant/research support: AbbVie, Pfizer, Consultant for: Pfizer, Abbvie, Roche/Chugai, Novartis, Medac, Pharm-Allergan