POS0931 RETENTION RATE AND TREATMENT RESPONSE OF BIOLOGICAL AGENTS IN ADVANCED SPINAL ANKYLOSIS AND BAMBOO SPINE: THE REAL LIFE DATA FROM THE HUR-BIO REGISTRY
Authors: B. Farisoğullari, G. K. Yardimci, E. C. Bolek, E. Bilgin, E. Duran, G. Ayan, Z. Özsoy, G. Sandal Uzun, L. Kiliç, A. Akdoğan, Ş. A. Bilgen, O. Karadag, S. Kiraz, A. İ. Ertenli, U. Kalyoncu
Journal: Annals of the Rheumatic Diseases (2021)

Background: Axial spondyloarthritis (axSpA) may lead to linear radiographic progression and progress to advanced spinal disease and finally to the bamboo spine (1). Objectives: To assess the demographic, clinical, disease activity and retention rates of patients using biological disease-modifying antirheumatic drugs (bDMARD) with advanced spinal disease and bamboo spine in the Hacettepe University Rheumatology Biologic Registry (HUR-BIO) cohort. Methods: In the HUR-BIO spondyloarthritis (SpA) registry were available 2952 patients. Of these, 774 patients with lumbar and cervical radiographs were included in the study. Advanced spinal ankyloses (99 patients) was defined as the presence of at least two intervertebral adjacent bridges at the lumbar and/or cervical spine level without bamboo spine. Bamboo spine (78 patients) was defined with a complete fusion of all lumbar and cervical spines. In addition, patients who diagnosed with axSpA for at least 10 years but no develop syndesmophytes on lumbar and cervical spine (92 patients) were used as a control group. Results: Both the bamboo spine and advanced spinal disease had higher age, higher BMI, more smoking (ever) and hip involvement compared to the without syndesmophytes group. Acute phase reactants, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing spondylitis disease activity Score-CRP (ASDAS-CRP) parameters were similar at the beginning of bDMARD in all groups. BASFI was higher in the bamboo spine group than in the without syndesmophytes group at last visit (Table 1). There were no differences between all groups in terms of the retention rate of the first bDMARD (Log rank p=0.86) (Figure 1). Conclusion: Data on the use of bDMARDs in SpA patients with bamboo spine are limited. This study showed that bDMARDs are an effective treatment option in SpA patients with bamboo spine with high disease activity. Similar drug retention rates were found compared to SpA patients with no syndesmophytes. Although the disease activity decreased similar rates in the groups, functional limitation continued in approximately half of the patients in bamboo spine patients. References: [1]Braun J et al. Staging of patients with ankylosing spondylitis: a preliminary proposal. Annals of the rheumatic diseases, 2002, 61.suppl 3: iii19-iii23. Table 1. Demographic, clinical characteristics and response to treatment in SpA groups. Without syndesmophytes n= 92 Advanced spinal disease n= 99 Bamboo spine n= 78 p Age, years˚ 42.2 ± 8.8 51.3 ± 10.2 55.5 ± 9.3 &lt; 0.001* Age at disease onset, years˜ 25.01 (11) 36.6 (20) 33.3 (18) &lt; 0.001* Male, n (% ) 55 (59.8) 78 (78.8) 66 (84.6) &lt; 0.001* Disease duration, years˜ 13.8 (5) 12.3 (15) 17.6 (13) &lt; 0.001* Delay in diagnosis, months˜ 12.02 (43) 36.01 (89) 36.01 (100) 0.013* HLA-B27 positivity/total, n (% ) 21/42 (50) 31/45 (69) 16/28 (57) 0.19 BMI˜ 26.3 (8) 29.7 (7) 29.4 (7) &lt; 0.001* Smoking (ever), n (% ) 56 (61) 78 (79) 58 (74) 0.019* Hip involvement, positivity/total (% ) 11/84 (13.1) 34/86 (39.5) 37/75 (49.3) &lt; 0.001* Onset Last Onset Last Onset Last p (onset ) p (last ) ESR, mm/h˜ 21.5 (34) 12.5 (18) 25.5 (29) 14.5 (17) 23 (31) 14 (14) 0.6 0.59 CRP, mg/dL˜ 1.5 (4) 0.4 (0.6) 1.7 (2) 0.65 (1) 1.8 (3) 0.64 (0.8) 0.4 0.001* ASDAS-CRP˜ 3.6 (0.8) 1.9 (1) 3.4 (0.9) 2 (1.2) 3.4 (0.8) 1.9 (1.4) 0.4 0.23 BASDAI score˜ 5.7 (2.6) 2.4 (4.5) 5.6 (3.3) 2.8 (3.1) 5.6 (3.2) 2.4 (3.3) 1 0.31 BASFI score˜ 5.4 (4) 2 (4) 4.5 (4) 3 (4) 6.5 (3) 3.9 (4.5) 0.1 0.002* BASFI score &gt; 4, n (% ) 29 (59) 23 (25) 29 (56) 32 (32) 27 (75) 36 (46) 0.1 0.014* ASAS PR, n (% ) 26 (28) 15 (15) 17 (22) 0.09 *p &lt;0.05, ˚ mean ± SD, ˜ median (IQR) SD: Standard deviation; IQR: Inter-quartile range BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; BASFI: Bath Ankylosing Spondylitis Functional Index; BMI: Body mass index; ESR: Erythrocyte sedimentation rate; CRP: C-reactive protein; ASAS PR: Assessment in SpondyloArthritis International Society partial remission; ASDAS: Ankylosing spondylitis disease activity score Figure 1. Retention rate of the first bDMARD Disclosure of Interests: None declared