Objective: To evaluate disease course and clinical usefulness in some categories of juvenile idiopathic arthritis (JIA) by applying newly developed Wallace definitions of remission off drugs.
Methods: In a retrospective study, charts of patients with chronic form of primary (idiopathic) arthritis followed from our center since 1970 were reviewed and clinical/laboratory variables were collected for further analysis.
Results: The cohort included 761 eligible patients [516 (67.8%) female, 245 (32.2%) male] with JIA. Mean disease onset age (+/- standard deviation) was 6.25 +/- 4.4 years (range 0.5-15.9). Disease mean duration to last visit was 10.02 +/- 4.31 years. Followup mean period was 7.6 +/- 6.4 years (range 1.5-35 yrs). A total of 247 (32.46%) patients achieved remission according to criteria [persistent oligoarthritis 153 (42.9%); extended oligoarthritis 15 (13.1%); seronegative polyarthritis 21 (22.4%); systemic arthritis 33 (33.7%); enthesitis related arthritis (ERA) plus juvenile psoriatic arthritis (JPsA) 25 (33.4%)]. No patients with seropositive polyarthritis achieved remission status (p < 0.001). In remitted patients the mean survival function (+/- standard error of the mean) before relapse calculated by Kaplan-Meier was of 20.9 (+/- 1.3) months overall: 21.7 (+/- 0.46) in persistent oligoarthritis, 25.0 (+/- 6.6) in extended oligoarthritis, 26.7 (+/- 13.2) in seronegative polyarthritis, and 17.6 (+/- 2.44) in ERA+JPsA (p > 0.1).
Conclusion: In our cohort about one-third of cases obtained a remission episode in 4 decades of observation, with a significant difference between oligoarthritis and other categories (p < 0.001) using the Kaplan-Meier method; the remission status duration before a relapse has been about 20 months, without a significant difference between JIA categories.