LAUSR

Background: Polymyalgia rheumatica (PMR) frequently co-occurs with giant cell arteritis (GCA). So far, a simple biomarker for detecting concomitant arterial inflammation in PMR patients is lacking. Furthermore, biomarkers predicting disease course in PMR are awaited. Objectives: We here investigated the diagnostic and prognostic value of acute-phase markers (ESR, CRP, IL-6, serum amyloid A) and angiogenesis markers (VEGF, soluble Tie2, angiopoietin-1, angiopoietin-2) in isolated PMR and PMR/GCA overlap patients. Methods: We prospectively included 39 treatment-naive PMR patients, of which 10 patients also showed evidence of large vessel GCA on FDG-PET/CT. Age-matched healthy controls (N=32) and infection controls (N=13) were included for comparison. Serum marker levels were measured by ELISA or Luminex. ROC and Kaplan Meier analyses were used to asses diagnostic and prognostic accuracy, respectively. Results: All acute-phase and angiogenesis markers, except angiopoietin-1, were higher in isolated PMR patients compared to HCs. Angiopoietin-2, ESR and soluble Tie-2 were significantly higher in patients with PMR/GCA overlap compared to isolated PMR patients. Angiopoeietin-2, but not soluble Tie2, outperformed ESR and CRP in discriminating patients with and without overlapping GCA (AUC 0.90). Moreover, high angiopoietin-2 levels were associated with long-term glucocorticoid requirement. Conclusion: Assessment of angiopoietin-2 at baseline may assist diagnosis of concomitant vasculitis in PMR. Moreover, high levels of angiopoietin-2 were associated with a unfavorable disease course in isolated PMR patients. These findings imply that angiopoietin-2 could be an interesting diagnostic and prognostic biomarker in PMR. Disclosure of Interests: Yannick van Sleen: None declared, Annemieke Boots Grant/research support from: grant from MSD in 2010-2015, Consultant for: I was a consultant for Grunenthal Germany 2016-2017, Employee of: I was an employee of Organon, Shering-Plough and MSD from 1991-2011, Wayel Abdulahad: None declared, Johan Bijzet: None declared, Maria Sandovici: None declared, Kornelis van der Geest: None declared, Elisabeth Brouwer Speakers bureau: Dr. Brouwer as an employee of the UMCG received speaker fees and consulting fees from Roche which were paid to the UMCG