FRI0646 EFFECT OF LONG-TERM MEDIUM-DOSE STEROID TREATMENT ON 18F-FDG PET/CT FINDINGS TO ASSESS VASCULAR AND MUSCULOESKELETAL INVOLVEMENT IN PATIENTSWITH POLYMYALGIA REUMATICA
Authors: D. Prieto-Peña, Monica Calderón-Goercke, Isabel Martínez-Rodríguez, Jose Ignacio Banzo, Miguel A. González-Gay, Ricardo Blanco
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Fluorine-18-fluorodeoxyglucose (<sup>18</sup>F-FDG) PET/CT has been proposed as a promising tool for assessing both musculoskeletal and vascular involvement in patients with polymyalgia rheumatica (PMR). Glucocorticoids (GC) may decrease the intensity of <sup>18</sup>F-FDG uptake. Therefore, performance of PET/CT before steroid therapy is recommended. However, in many patients with PMR, large vessel vasculitis (LVV) is precisely suspected because of steroid resistance after a long-term treatment with GC <sup>1</sup>. <h3>Objectives</h3> Our aim was to assess the influence of long-term medium-dose treatment on <sup>18</sup>F-FDG uptake to discern if <sup>18</sup>F FDG PET/CT could be useful to evaluate musculoskeletal and vascular involvement in patients under treatment with GC. <h3>Methods</h3> Single-center study of 75 patients with PMR diagnosis based on 2012 EULAR/ACR criteria. All patients underwent a PET/CT scan due to LVV suspicion based on the presence of atypical symptoms and/or persistent symptoms despite steroid therapy. We considered two groups: a) Steroid-naïve PMR patients. b) Steroid-resistant PMR patients. Both musculoskeletal and vascular <sup>18</sup>F-FDG uptake was assessed. The statistical analysis was performed with SPSS. Student's t test or Mann-Whitney U test was used to compare continuous variables, and Chi-squared test or Fisher's exact test for categorical variables as appropriate. <h3>Results</h3> We evaluated 75 patients, 27 men and 48 women (mean age ± SD: 68.2 ± 10.7 years). PET/CT was performed in 14 steroid-naïve PMR patients (18.7%) and 61 steroid-resistant PMR patients (81.3%). Patients under steroid treatment had received a median dose of Prednisone of 10.0 [5.0-15.0] mg/day during 9.0 [2.0-22.0] months. Vascular <sup>18</sup>F-FDG uptake was more frequently detected in steroid-naïve patients. In regard with musculoskeletal <sup>18</sup>F-FDG uptake, no statistically significant differences were seen between both groups (<b>TABLE</b>). <h3>Conclusion</h3> Vascular <sup>18</sup>F-FDG uptake detection was higher in PMR patients with LVV suspicion who had never received GC. However, PET/CT was also useful to detect vascular involvement in most of the patients under a long-term medium-dose steroid treatment. <h3>Reference</h3> [1] D. Prieto-Peña, I. Martínez-Rodríguez, J. Loricera, et al. Predictors of positive (18)F-FDG PET/CT-scan for large vessel vasculitis in patients with persistent polymyalgia rheumatica. Semin Arthritis Rheum; 2018): Doi: 10.1016/j.semarthrit.2018.05.007. [Epub ahead of print] <h3>Disclosure of Interests</h3> D. Prieto-Peña: None declared, Monica Calderón-Goercke: None declared, Isabel Martínez-Rodríguez: None declared, Jose Ignacio Banzo: None declared, Miguel A González-Gay Grant/research support from: Prof. MA Gonzalez-Gay received grants/research supports from Abbvie, MSD, Jansen and Roche., Speakers bureau: Consultation fees/participation in company sponsored speaker's bureau from Pfizer, Lilly, Sobi, Celgene, Novartis, Roche and Sanofi., Ricardo Blanco Grant/research support from: Abbvie, MSD, and Roche, Consultant for: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen, Speakers bureau: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen