APPLICATION OF THE DIFFICULT-TO-TREAT CONCEPT FOR AXIAL SPONDYLOARTHRITIS

L. Berbel Arcobé, M. Roig Kim, E. Brugarolas Martinez, A. Domingo Carnice, P. Vidal Montal, M. Aguilar Coll, J. Palacios Olid, P. Maymo Paituvi, X. Juanola-RouraBellvitge University Hospital, Rheumatology, L’Hospitalet de Llobregat, Spain Bellvitge University Hospital, Clinical Pharmacology, L’Hospitalet de Llobregat, Spain  Background The term “Difficult-to-Treat” (D2T) includes those patients who have persistent disease activity despite of having undergone several guideline-based treatments. This concept has been defined by EULAR for rheumatoid arthritis (RA) , thus could be analogously used for patients with Axial Spondyloarthritis (axSpA). In a recent publication authors suggest that, among other criteria, axSpA patients could be classified as D2T when they require three or more biological drugs (bDMARDs) to control their disease. Objectives To describe the characteristics of axSpA patients who have undergone treatment with bDMARDs from a third-level university hospital and compare those who have received a maximum of two bDMARDs (group A) versus those who have received three or more (group B). Methods Descriptive, retrospective and unicentric study. Patients with axSpA diagnosis based on ASAS classification criteria, from March 2011 to December 2022, pulled from a specific database were included. They were separated into two groups according to the number of bDMARDs they had been under. Sociodemographic, clinical, radiographic and therapeutic variables were gathered. Results A total of 193 patients met the ASAS criteria for the diagnosis of axSpA and had received at least one bDMARD. The studied variables for each group are summarised in Table 1. Out of 193 patients (71% men; mean age 46,4 +/- 14 years old) 158 (81,9%) belonged to group A and 35 (18,1%) belonged to group B. There were no statistically significant differences between both groups. However, a tendency towards history of psoriasis, positive HLA B27 and elevated CRP at diagnosis was observed in those patients from group B. Conclusion The need of three or more bDMARDs in SpA is not infrequent in patients with axSpA and has similar proportions to RA. There has not been an agreement on stablished criteria for a D2T axSpA, but they could resemble those already defined for RA. Describing D2T for axSpA would be useful to identify those interrelated factors that may be associated with an increased activity upon diagnosis (high CRP) or the presence of extra musculoskeletal manifestations (psoriasis). References Nagy G, Roodenrijs NMT, Welsing PMJ, et al., EULAR definition of difficult-to-treat rheumatoid arthritis, Ann Rheum Dis 2021;80:31–35. Wendling D, Verhoeven F, Prati C, Is the Difficult-to-Treat (D2T) concept applicable to axial spondyloarthritis?, Joint Bone Spine 2022. Table 1. Included patients’ sociodemographic, clinical and therapeutic variables. Group A n= 158 Group B n= 35 p-value Age (yr) Mean age 46,5 ± 14,2 48,8 ± 14 0.391 Age at beginning of symptoms 28,3 ± 10,7 27,7 ± 11,7 0.797 Age at diagnosis 34,3 ± 12,1 32,4 ± 11,8 0.384 Sex Male 118 (74,7%) 20 (57,1%) 0.038 Female 40 (40%) 15 (42,9 %) HLA B27 Positive 111 (13%) 23 (65,7%) 0.387 Negative 41 (27%) 12 (34,3%) High CRP Yes 106 (67%) 29 (82,9%) 0.066 No 52 (32,9%) 6 (17,1%) Uveitis Yes 32 (20,3%) 6 (17,1%) 0.675 No 126 (79,8%) 29 (82,9%) Psoriasis Yes 12 (7,6%) 7 (20%) 0.026 No 146 (92,4 %) 28 (80%) Familiar history of axSpA Yes 31 (19,6%) 7 (20%) 0.959 No 127 (80,4%) 28 (80%) Peripheral arthritis Yes 67 (42,4%) 17 (48,6%) 0.506 No 91 (57,6%) 18 (51,4%) Enthesitis (heel) Yes 54 (34,2%) 10 (28,6%) 0.524 No 104 (65,8%) 25 (71,4%) Dactylitis Yes 8 (5%) 4 (11,4%) 0.158 No 150 (94,9%) 31 (88,6%) axSpA type r-axSpA (AS) 110 (69,6%) 21 (60%) 0.270 EnA 28 (17,7%) 7 (20%) 0.752 Juvenile SpA 4 (2,5%) 0 (0%) 0.341 Ps SpA 6 (3,8%) 4 (11,4%) 0.065 nr-axSpA 10 (6,3%) 3 (8,6%) 0.632 Smoking history Non-smoker 81 19 0.746 Ex-smoker or active smoker 77 16 axSpA: axial Spondyloarthritis; CRP: C-Reactive Protein; r-axSpA: radiographic axial Spondyloarthritis; AS: Ankylosing Spondylitis; EnA: Entheropatic Arhtritis (Inflammatory Bowel Disease-Associated Spondyloarthritis); Juvenile SpA: Juvenile Spondyloarthritis; Ps SpA: Psoriasic Spondyloarthritis; nr-axSpA: non-radiographic Spondyloarthritis Acknowledgements: NIL. Disclosure of Interests None Declared. Keywords: Real-world evidence, Spondyloarthritis, bDMARD DOI: 10.1136/annrheumdis-2023-eular.2648Citation: , volume 82, supplement 1, year 2023, page 1696Session: Spondyloarthritis - treatment (Publication only)