POS0521 REAL WORLD EVIDENCE SHOWS THAT REPEAT MRI IS OF UTILITY IN THE EVALUATION OF TREATMENT NON-RESPONSE IN AXIAL SPONDYLOARTHRITIS- DATA FROM A TERTIARY RHEUMATOLOGY CENTRE
Authors: J. Weddell, R. Shah, L. Rossi, P. Robinson, A. Barr, C. Vandevelde, J. Freeston, D. Mcgonagle, H. Marzo-Ortega
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> The use of MRI of the spine and sacroiliac joints is well established in axial Spondyloarthritis (axSpA) diagnosis. However, its utility in disease monitoring, in particular the assessment of treatment non-response is unclear, with limited and conflicting data on the relationship between inflammatory changes on MRI and outcome measures, resulting in the most recent ASAS/EULAR guidelines recommending against routine use of MRI in the assessment of treatment response in axSpA. Nevertheless, in the clinical setting, MRI is utilised to exclude the presence of inflammation or an alternative diagnosis in those cases where there is no response or loss of previous response to biologic or targeted synthetic disease modifying drugs (b/ts DMARDs) in some patients, with substantial cost implications and unclear benefits. <h3>Objectives:</h3> To explore the current use of MRI to assess disease activity in axSpA in a large tertiary centre, in particular its utility in exploring treatment non-response and its impact on treatment decision making at the bedside. <h3>Methods:</h3> As part of a service evaluation audit, MRIs of the whole spine and SIJ performed under the inflammatory back pain protocol at the Leeds Teaching Hospitals Trust, in patients with a prior diagnosis of axSpA (nr-axSpA, r-axSpA or axial psoriatic spondyloarthritis [axPsA]) who had an MRI performed to assess worsening of back pain symptoms or reporting non-response to b/ts DMARDs between May 2020 and May 2023 were identified from radiology request data. Data on demographics, pre-treatment MRI findings (if available), current medication, and inflammatory markers were extracted from the clinical notes. Data on MRI findings consistent with inflammatory changes related to axSpA (positive scan) or alternative findings, were extracted from the local radiologist's report. <h3>Results:</h3> Overall, 179 patients had an MRI performed to explore worsening symptoms of back pain or treatment non-response, of which 155 had axSpA (81 r-axSpA, 74 nr-axSpA) and 24 axPsA. In the axSpA group (n=155) 56.7% were male, 69.0% HLA-B27 positive, 21.2% and 35.4% current smokers and ex-smokers respectively, 12.9% had psoriasis and 33% had peripheral arthritis. Of the 24 axPsA patients, 58.3% were male, 20.8% HLA-B27 positive, 25% current and 29% former smokers, 100% had a history of psoriasis, and 80.3% peripheral arthritis. A pre-treatment MRI scan was available in 119 patients (66.5%), of which 100 (84.0%) were positive with inflammatory lesions seen either solely on the spine (n=9), sacroiliac (n=57) or combined SIJ/spinal joints (n=34). Overall, 122 patients (68.2%) were on bDMARD therapy (TNFi [n=91], IL-17Ai [n=21] JAKi [n=4], other [n=6]). MRI was positive for inflammatory lesions in 53.1% (n=95) of patients, located in the spine (n=19), sacroiliac joints (n=36) or both (n=40). Of the 21 patients with a negative (no inflammation) pre-treatment MRI, 6 (3 Males, Mean age 46.8, 4 HLA-B27+ve) were positive on the treatment non-response scan. Patients with active inflammation in the repeat scan were more likely to have their bDMARD switched or treatment escalated (61% vs 26%) as a result. Other important findings included spinal stenosis (n=7), disc disease (n=19), vertebral fractures (n=3) and potential malignancy (n=1). <h3>Conclusion:</h3> In our practice, MRI is of utility in the assessment of treatment non-response in axSpA, aiding treatment decision by leading to a change in therapy in half of patients and excluding alternative pathologies, such as vertebral fractures and disc disease which may also affect components of disease activity scores in axSpA. Further research exploring the association of MRI findings with clinical outcomes, including economic evaluation of routine MRI to assess disease activity in axSpA is warranted. <b>Table 1.</b> Demographics and findings of patients undergoing MRI to assess disease activity. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> Disclosure NIL. <h3>Disclosure of Interests:</h3> Jake Weddell: None declared, Rahul Shah: None declared, Lara Rossi: None declared, Philip Robinson: None declared, Andrew Barr: None declared, Claire Vandevelde UCB and Janssen, Jane Freeston Novartis, Ferring, Dennis McGonagle Abbvie, MBS, UCB, Pfizer, Eli-lilly, Janssen, Celgene and Novartis, Abbvie, MBS, UCB, Pfizer, Eli-lilly, Janssen, Celgene and Novartis, Helena Marzo-Ortega Abbvie, Biogen, Eli-Lilly, Janssen, Novartis, Pfizer and UCB, Abbvie, Biogen, Eli-Lilly, Janssen, Novartis, Pfizer, Takeda and UCB, Eli-Lilly, Janssen, Moonlake, Novartis and UCB, Janssen, Novartis, Pfizer and UCB.