Date: Monday, November 9, 2020
Session Type: Poster Session D
Session Time: 9:00AM-11:00AM
Background/Purpose: The OMERACT Ultrasound (US) large vessel vasculitis task force has recently defined the US appearance of normal axillary arteries (AA) and the key elementary US lesions in acute giant cell arteritis (GCA) of the AA (i.e.:“non-compressible halo sign”). The aim of the present study was to assess the reliability of a new OMERACT definition for the US appearance of chronic GCA lesions of the AA in a web-based reliability exercise (Table 1)
Methods: The reliability exercise was performed using a REDCap. One-hundred-fifty anonymized still images from AA, were assessed (50 each from chronic and acute GCA, and 50 from healthy individuals). Chronic GCA patients had a disease duration of more than one year and were in remission. Acute GCA patients had new-onset disease with glucocorticoid treatment duration ≤1 week. The members of the OMERACT Large Vessel Vasculitis Ultrasound Working Group (n=23, all ultrasound experts in GCA) were asked to assign all images to the categories of normal, acute GCA or chronic GCA applying the definitions agreed in previous Delphi exercises. In order to assess the intra-observer reliability, all task force members were asked to repeat the reliability exercise in a time range of at least two weeks later and using the same images presented in a different order. Light’s κ were used for evaluating intra- and inter-reader reliability, respectively. Κ values of 0–0.2 were considered slight, 0.2–0.4 fair, 0.4–0.6 moderate, 0.6–0.8 substantial and 0.8–1 excellent.
Results: The response rate for both rounds was 100%. The reliability of the new OMERACT definition for the US appearance of chronic GCA of the AA was substantial to excellent with Light’s kappa values of 0.79-0.80 for inter-reader reliability and mean Cohen-kappa values of 0.88. The mean inter-rater agreements were 86-87%. The mean intra-reader agreements were 92% (Table 2).
Conclusion: Inter- and intra-observer agreement on the evaluation of US still images from normal, acute and chronic GCA AA was substantial to excellent when applying the new OMERACT definitions for key elementary US lesions in GCA of the AA. Further exercises are planned in order to test the reliability in patients with chronic GCA US changes of the AA.
To cite this abstract in AMA style:Schaefer V, Chrysidis S, Carrara G, Schmidt W, Bruyn G, Dasgupta B, De Miguel E, Diamantopoulos A, Duftner C, Fredberg U, Nielsen B, Hartung W, Hocevar A, Iagnocco A, Juche A, Kermani T, Lorenzen T, Macchioni P, Milchert M, Døhn U, Monti S, Mukhtyar C, Ponte C, Scire C, Terslev L, Seitz L, Dejaco C. Definitions and Reliability Assessment of Chronic Ultrasound Lesions of the Axillary Artery in Giant Cell Arteritis: A Study from the OMERACT Large Vessel Vasculitis Ultrasound Working Group [abstract]. Arthritis Rheumatol. 2020; 72 (suppl 10). https://acrabstracts.org/abstract/definitions-and-reliability-assessment-of-chronic-ultrasound-lesions-of-the-axillary-artery-in-giant-cell-arteritis-a-study-from-the-omeract-large-vessel-vasculitis-ultrasound-working-group/. Accessed May 7, 2021.
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