AB0354 FDG-PET-DETECTED LARGE VESSEL VASCULITIS DOES NOT PREDICT DISEASE OUTCOME IN PATIENTS WITH GIANT CELL ARTERITIS AND POLYMYALGIA RHEUMATICA

Background: Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are tightly associated inflammatory conditions of the elderly [1]. Both disorders can exhibit an increased articular vascular uptake 18-fluorodeoxyglucose (18-FDG) at positron emission tomography (PET)/computed (CT) scan [2]. Objectives: This study evaluated if large-vessel vasculitis (LVV) detected by PET/CT in patients with PMR and/or cranial GCA had a negative prognostic value. Methods: 108 (35 men 73 women) median age 74 years (range 50-92 years) were prospectively enrolled our centre over 4 years. was diagnosed Bird et al. criteria ACR criteria. Six died shortly after first visit (V 0 ) six lost follow-up. Of remaining 96 patients, 77 classified as PMR, 6 13 affected both diseases. At V , underwent clinical, laboratory evaluation, stratified according to presence or not LVV. Follow-up visits performed every months for 40 months. Disease outcomes were: prednisone (PDN) use its cumulative dosage, need methotrexate (MTX), number relapses, patients’ death, disease activity score (PMR-DAS). The independent variables age, sex, duration, fever, C-reactive protein (CRP) concentration, platelet count (PLT), GCA, degree joint FDG, predictive role LVV tested multiple regression. Results: seen 47 (49 %), 31 10 Patients without did significantly differ terms demographic parameters except non-significant higher PLT Clinical per considered together, change between PET+ PET- (table 1). Lastly, none variables, including LVV, could predict outcomes. Conclusion: PET-detected diagnosis does seem factor GCA. As consequence, routine investigation is indicated outcome. References: [1]Dejaco C, Duftner Buttgereit F, Matteson EL, Dasgupta B. spectrum giant rheumatica: revisiting concept disease. Rheumatology (Oxford). 2017 Apr 1;56(4):506-515. doi: 10.1093/rheumatology/kew273. PMID: 27481272. [2]Blockmans D, Coudyzer W, Vanderschueren S, Stroobants Loeckx Heye S Relationship fluorodeoxyglucose large vessels late aortic diameter arteritis. 2008 Aug;47(8):1179-84. 10.1093/rheumatology/ken119. Epub May 31. 18515868. Table 1. Clinical, imaging features Features p Morning stiffness (min) 30 (0-480) 60 (0-360) 0.20 Haemoglobin (g/dL) 12.3±1.5 12.6±1.5 0.28 Platelets (x 3 /mm 349 (108-643) 297(159-571) 0.08 (mg/dL) 35.5 (3.4-149) 36.2 (2-149) 0.54 Erythrocyte sedimentation rate (mm/h) 62.5 (10-120) 57.5 0.29 Total Vascular Score PET 20 (4-41) (0-12) Joint 18 (5-30) (5-32) 0.77 Disclosure Interests: None declared