Objective To determine predictive/predictable factors of relapse in rheumatoid arthritis (RA) patients undergoing biologic Disease-Modifying Anti-Rheumatic Drugs (bDMARDs) dose reduction/discontinuation.

Patients and methods RA patients receiving the same bDMARD for more than 1 year, in Simplified Disease Activity Index (SDAI) remission, were selected in an observational monocentric real-life study. The 18-month follow-up included spacing (6 months) and withdrawal (12 months) periods of bDMARD. Clinical, biological and ultrasonographic (US) parameters were collected regularly. Relapse was defined by SDAI>11.

Results Fifty-three RA patients (mean age: 58 years; 72% women; median duration: 11 years) were enrolled. Forty-two received anti-cytokinic bDMARD targeting tumour necrosis factor (n=39) or interleukin-6R (n=3) and 11 were treated by abatacept. The number of relapses during the spacing and discontinuation periods were 19 and 20, respectively. After 18 months of follow-up, among the 53 patients, 12 maintained bDMARD-free remission, 39 had relapsed and 2 were lost of follow-up. Median time to relapse was 11.8 months. In multivariate analysis, baseline factors predictive of relapse were corticosteroid intake, female gender, longer disease duration and no methotrexate intake with bDMARD. Concerning the survival analysis, also taking into account the factors of predictability, the main risk factor of relapse after discontinuation was an increase of SDAI >0 during the spacing period (p=0.03). US findings were not contributive.

Conclusion In the context of RA in remission under bDMARDs, variation of SDAI during the dose-reduction phase is more relevant than baseline parameters to predict success of drug withdrawal.