LAUSR

Background Ankylosing spondylitis (AS) is a chronic and progressive condition of the spine, which is the most common form of spondyloarthritis (SpA). Although anti-TNF agents are the most effective therapy for AS or SpA, it is recommended as the second-line treatment for individuals who have persistently high disease activity despite treatment with at least 2 non-steroidal anti-inflammatory drugs (NSAIDs), intolerance or contraindication to NSAIDs. Changes in ankylosing spondylitis disease activity score (ASDAS) are often measured to reflect outcomes in AS trials. However, anti-TNF does not always maintain long-term remission. There is limited evidence about remission rate of 6 months treatment from real-world AS cohorts. Objectives The purpose of this study is to compare the remission rate of AS patients among biologics users or non-biologics users from China Ankylosing Spondylitis/Spondyloarthritis Prospective Imaging Cohort (CASPIC). Methods CASPIC is an ongoing prospective cohort established by a smart management system[Smart Management System for Spondyloarthritis (SMSP)]. Clinic visits were scheduled based on visits reminder set by rheumatologists (1~6 months). Anti-TNF users were defined as patients who used biological agents during the follow-up period and the baseline was defined as the start time to use the biological agents. Non-biologics users were served as control groups. ASDAS was calculated to assess disease activity in AS. Generalise additive mixed model and curve fitting were used to show the difference between two groups. Results There were 841 AS patients in this cohort, 83.4% were male, with mean (±SD) age 30.8 (±8.8) years, mean time since diagnosis 8.3 (±6.1) years (table 1). Mean duration of anti-TNF treatment was 4.1 (±3.5) months. Significant improvements were observed in ASDAS (table 2). Anti-TNF users had more serious disease activity, and better clinical improvement (figure 1). If the duration of anti-TNF treatment was less than 6 months, relapsed rates were higher than those with longer than 6 months of anti-TNF (figure 1).Abstract AB0834 – Table 1 Baseline characteristics mean(SD)/N(%) Anti-TNF users(n=633) Non-anti-TNF users(n=208) P Age 31.2 (9.0) 29.7 (8.1) 0.040 Disease duration 8.3 (6.2) 8.4 (5.7) 0.869 ASDAS-CRP 2.1 (1.0) 2.6 (1.1) <0.001 Male 535 (84.5%) 166 (79.8%) 0.114 HLA-B27 positivity 495 (87.3%) 176 (89.3%) 0.451 With NSAIDs 526 (99.1%) 162 (98.2%) 0.356Abstract AB0834 – Table 2 Change in ASDAS per month Anti-TNF users Non-anti-TNF users P Non-adjusted −0.027 (-0.043,–0.011) −0.065 (-0.094,–0.036) <0.01 Adjusted −0.032 (-0.048,–0.015) −0.063 (-0.092,–0.033) <0.01 Adjusted model: gender, age, disease duration, whether NSAIDs were usedAbstract AB0834 – Figure 1 Curve Fitting of Change in ASDAS Conclusions Anti-TNF therapy had superior improvement than NSAIDs therapy. Anti-TNF should be used for more than 6 months to achieve better and sustained remission and prevent recurrence. Disclosure of Interest None declared