Evaluation of flare rate and reduction strategies for bDMARDs in juvenile idiopathic arthritis: real world data from a single-centre cohort.

This study aimed to determine the flare rate (FR) in a cohort of Juvenile Idiopathic Arthritis (JIA) patients with tapered or abruptly discontinued biologic disease-modifying anti-rheumatic drugs (bDMARDs) and to identify predictors of flare. This retrospective observational study included 191 bDMARD dose-reduction events in patients with JIA followed-up at a referral hospital during the period 2000-2019. FR was analysed according to reduction strategies. To identify predictors of flare, Kaplan-Meier and Cox-regression models were plotted at 6 months (6 m), 12 months (12 m) and 24 months (24 m) following tapering (TP) or withdrawal (WD). 165 episodes of TP and 71 episodes of WD were included; 45 episodes where treatment was withdrawn after TP were included in both strategies. FR after TP was 13.4% at 6 m and increased up to 26.6% at 12 m and 51.4% at 24 m. After WD, FR was higher, 52.1% of events had a flare at 6 m and 67.6% at 12 m. Previous TP did not increase time in remission after WD of bDMARDs in the Kaplan-Meier analysis. Factors associated with flares were identified after TP at 6 m: female sex, higher number of previous bDMARDs and longer time on bDMARD treatment were positively associated with flares. Polyarticular subtype and younger age at diagnosis were associated with flares at 12 and 24 m after TP. No factors were identified in multivariable analysis after WD. TP is a successful strategy to maintain remission with lower bDMARD doses. Previous TP of bDMARDs does not seem to increase time in remission after WD.