SAT0407 FOLLOW-UP EXAMINATION FOR THE DETECTION OF POTENTIAL PSORIATIC ARTHRITIS BY FLUORESCENCE OPTICAL IMAGING – IN COMPARISON TO MUSCULOSKELETAL ULTRASOUND
Authors: J. Büttner, A. M. Glimm, G. Kokolakis, M. Erdmann-Keding, G. R. Burmester, J. Klotsche, S. Ohrndorf
Journal: Annals of the Rheumatic Diseases (2020)

Background: Up to 30% of all plaque-type psoriasis patients develop psoriatic arthritis (PsA) (1). Early diagnosis of PsA can be difficult due to its heterogenous manifestation and the lack of disease- specific biomarkers, but it is crucial for disease outcome. Recently, our group has shown that fluorescence optical imaging (FOI) can be a helpful diagnostic tool for early PsA diagnosis since it can differentiate between patients with confirmed PsA and suspected PsA (2). Objectives: To follow-up patients by FOI with confirmed and suspected PsA with special focus on the group of patients in which PsA could be confirmed between baseline and follow-up – and to compare with the findings of musculoskeletal ultrasound (US). Methods: Patients included in our previous study (1) were re-evaluated by FOI of both hands in a standardized manner using the predefined phases 1-3 (p1-p3) and the PrimaVistaMode (PVM). US in greyscale (GS) and power Doppler (PD) were performed of the clinically dominant hand (for tenderness and/or swelling) in the dorsal and palmar view at wrist, MCP, PIP and DIP 2-5 joint levels for synovitis and tenosynovitis. Subsequently, a comparison of the findings in the affected joints was performed using US as the reference method. Furthermore, AUC was calculated to show the extent to which a new joint inflammation was associated with a change in diagnosis. Results: Of the 60 patients initially examined (1), 30 patients (dropout rate 50%) were followed-up approximately 3 years later. The patients were newly divided into 3 groups: Diagnosed PsA (n=14, Group I), still suspected PsA, (n=6, Group II) and in-between diagnosed PsA (n=10, Group III). Patients with a change in the diagnosis from suspected to diagnosed PsA (Group III) showed a significantly increased prevalence of joints with pathological findings in FOI (46% at baseline, 88% at follow-up; p=0.046), with an unchanged joint distribution pattern, i.e. with a dominant involvement of the DIP joints. Compared to baseline, patients of group III were three times more common to show enrichment in p3 in FOI at follow-up (1.7% vs. 7.0%; p=n.s.). Newly detected pathologic joints by FOI (PVM, p2) and US at follow-up were positively associated with the change of diagnosis from suspected PsA to confirmed PsA (FOI: AUC 0.78; GSUS: AUC 0.77).Using US in greyscale as reference, inflammatory changes in the joints were diagnosed in all 3 cohorts by means of FOI in P1 and P3 with high specificity (Group III: 90.6%, Group II: 97.5%, Group I: 94.2%) and low sensitivity (Group III: 24.4%, Group II: 20.3%, Group I: 19.8%). Conclusion: FOI appears to be helpful to differentiate between acute and chronic disease stages. Furthermore, it is specific for detecting inflammatory changes in the joints of the hands in PsA – in comparison to US. FOI could thereby become a helpful tool as a “dermatological-screening” method to select psoriasis patients with indication for further rheumatological evaluation. References: [1]Zachariae H. Prevalence of Joint Disease in Patients with Psoriasis: Implications for therapy. Am J Clin Dermatol. 2003;4(7):441–447. Review. [2]Erdmann-Keding M, Ohrndorf S, Werner SG, et al. Fluorescence optical imaging for the detection of potential psoriatic arthritis in comparison to musculoskeletal ultrasound. J Dtsch Dermatol Ges. 2019;17(9):913-921. Disclosure of Interests: Juliane Büttner: None declared, Anne-Marie Glimm: None declared, Georgios Kokolakis: None declared, Magdalena Erdmann-Keding: None declared, Gerd Rüdiger Burmester Consultant of: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Speakers bureau: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Jens Klotsche: None declared, Sarah Ohrndorf: None declared