POS1373 CHARACTERIZATION OF PRECLINICAL RHEUMATOID ARTHRITIS AND PSORIATIC ARTHRITIS BY CLINICAL AND IMAGING PARAMETERS AND THEIR POTENTIAL ROLE IN THE PREDICTION OF ARTHRITIS
Authors: N. Nendel, J. Klotsche, G. Schmittat, M. Backhaus, G. Krönke, G. R. Burmester, G. Kokolakis, S. Ohrndorf
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> For the development of both rheumatoid arthritis (RA) and psoriatic arthritis (PsA) concepts of (chronic) disease development from asymptomatic over arthralgia to arthritis have been proposed [1,2] and first promising studies on disease prevention/interception exist [3-5]. In early disease stages, it can be difficult to distinguish preclinical RA from PsA, e.g., because antibodies are not yet detectable in preRA (RF and/or ACPA). <h3>Objectives:</h3> To characterize preclinical RA and PsA by clinical and imaging parameters using musculoskeletal ultrasound (MSUS) and fluorescence optical imaging (FOI) in patients with arthralgia (without clinical arthritis) and suspected RA or PsA and to determine their potential role in disease prediction. <h3>Methods:</h3> Adult patients with inflammatory arthralgia suspicious for RA or PsA with confirmed psoriasis (PsO) are continuously included in this project. These patients are reviewed for the development of clinical arthritis (in case of suspected RA) or clinical arthritis, dactylitis or enthesitis (in case of suspected PsA) over three years with scheduled visits at baseline, after 4, 12, 24, and 36 months. At each visit, the following examinations are performed: TJC-68, SJC-66, DAS28-ESR, SDAI, CDAI (Simple/Clinical Disease Activity Index), patient's global disease activity and pain (each VAS 0-100mm), autoantibodies (RF/ACPA) as well as imaging parameters by MSUS in greyscale (GS)/power Doppler (PD) and by FOI. MSUS is done for the detection of synovitis and tenosynovitis (both wrists, MCP and (P)IP1-5, and MTP1-5) in GS and PD (each 0-3), and enthesitis (10 sites). FOI of both hands is performed by the Xiralite method in a standardized manner using PrimaVista Mode (PVM) and three predefined phases (p1-p3). <h3>Results:</h3> Forty-eight participants have been included: 25 as preclinical RA (22 female, mean age 46.0±12.2, mean symptom duration 14.3±18.0 months; 28% RF+/32% ACPA+) and 23 as preclinical PsA (14 female, mean age 48.0±9.3, mean symptom duration 15±12.3 months; 0% RF+/4.3% ACPA+). Baseline clinical and imaging data of the two groups are presented in Table 1 and <b>Table 2</b>. One PsO patient (4.3%) had a PD positive enthesitis in one enthesis at baseline. So far, seven out of 25 (28%) and three out of 23 patients (13%) have been diagnosed with RA and PsA over time. For the prediction of RA, SDAI (AUC 0.71) as well as FOI in PVM (AUC 0.70) and p2 (AUC 0.71) have a certain predictive power. For the prediction of PsA, VAS for global disease activity (AUC 0.75) and pain (AUC 0.70) as well as GS-tenosynovitis (AUC 0.77) have a certain predictive power. <h3>Conclusion:</h3> Patients with preclinical RA compared to preclinical PsA have lower clinical disease activity scores, but higher scores on imaging (PD+/FOI-p1). For the prediction of RA, FOI could be a promising tool. Further investigation, also to better distinguish differences of preclinical RA/PsA are needed. <h3>REFERENCES:</h3> [1] van Steenbergen HW, et al. Nat Rev Rheumatol. 2018 Jan;14(1):32-41. [2] Zabotti A, et al. Curr Rheumatol Rep. 2020 May 16;22(6):24. [3] Krijbolder DI, et al. Lancet. 2022 Jul 23;400(10348):283-294. [4] Rech J, Schett G. Lancet. 2022 Jul 23;400(10348):253-255. [5] Zabotti A, et al. Dermatol Ther (Heidelb). 2022 Jan;12(1):5-8. <h3>Acknowledgements:</h3> This project is supported by the 'Advanced Clinician Scientist Program (ACSP)' of the German Society of Internal Medicine (DGIM). <h3>Disclosure of Interests:</h3> Norman Nendel: None declared, Jens Klotsche: None declared, Gabriela Schmittat: None declared, Marina Backhaus: None declared, Gerhard Krönke: None declared, Gerd R. Burmester: None declared, Georgios Kokolakis: None declared, Sarah Ohrndorf Novartis; Janssen; Mylan, Speakers' honoraria or travel expense reimbursements by: AbbVie, Amgen, BMS, Galapagos, Janssen, Mylan, Novartis, UCB, Novartis; GSK; AbbVie