Predictors of Loss of Remission and Disease Flares in Patients with Axial Spondyloarthritis Receiving Antitumor Necrosis Factor Treatment: A Retrospective Study

Objective. The aim of this study was to evaluate rate and predictive factors of loss of remission and disease flare in patients with axial spondyloarthritis (axSpA) receiving antitumor necrosis factor (anti-TNF) treatment. Methods. In this retrospective multicenter study, patients with axSpA, according to the Assessment of Spondyloarthritis international Society (ASAS) criteria, treated with adalimumab, etanercept, or infliximab with a minimum followup of 12 months and satisfying the ASAS partial remission criteria and/or Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease were studied. Disease flare was defined as a Bath Ankylosing Spondylitis Disease Activity Index score > 4.5 or ASDAS score > 2.5 on at least 1 occasion. Results. One hundred seventy-four patients with axSpA were studied. After a median [interquartile range (IQR)] followup of 4 years (2-6), 37 patients (21.2%) experienced a loss of remission and 28 (16.1% of the whole study group) a disease flare. Median (IQR) duration of remission in patients who lost this status was 1 year (0.625-2). Higher median erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values, continuous nonsteroidal antiinflammatory drug (NSAID) use, and an ASDAS-CRP >= 0.8 during the remission period were significantly associated with both loss of remission and disease flare. At the multivariate analysis, continuous NSAID intake (OR 4.05, 95% CI 1.4-11.74, p = 0.010) and ESR > 15 (OR 2.90, 95% CI 1.23-6.82, p = 0.015) were the only factors predictive of disease reactivation. Conclusion. In this study, loss of remission and disease flares occurred, respectively, in about 21% and 16% of the patients with axSpA who achieved a state of remission while receiving anti-TNF therapy. Residual disease activity was associated with disease reactivation.