Instrument selection for the ASAS core outcome set for axial spondyloarthritis

Victoria Navarro-Compán*, Anne Boel, Annelies Boonen, Philip J Mease, Maxime Dougados, Uta Kiltz, Robert B M Landewé, Xenofon Baraliakos, Wilson Bautista-Molano, Praveena Chiowchanwisawakit, Hanne Dagfinrud, Lara Fallon, Marco Garrido-Cumbrera, Lianne Gensler, Bassel Kamal ElZorkany, Nigil Haroon, Yu Heng Kwan, Pedro M Machado, Walter Maksymowych, Anna MoltoNatasha de Peyrecave, Denis Poddubnyy, Mikhail Protopopov, Sofia Ramiro, In-Ho Song, Salima van Weely, Désirée van der Heijde

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Web of Science)


OBJECTIVES: To define the instruments for the Assessment of SpondyloArthritis international Society-Outcomes Measures in Rheumatology (ASAS-OMERACT) core domain set for axial spondyloarthritis (axSpA).

METHODS: An international working group representing key stakeholders selected the core outcome instruments following a predefined process: (1) identifying candidate instruments using a systematic literature review; (2) reducing the list of candidate instruments by the working group, (3) assessing the instruments' psychometric properties following OMERACT filter 2.2, (4) selection of the core instruments by the working group and (5) voting and endorsement by ASAS.

RESULTS: The updated core set for axSpA includes seven instruments for the domains that are mandatory for all trials: Ankylosing Spondylitis Disease Activity Score and Numerical Rate Scale (NRS) patient global assessment of disease activity, NRS total back pain, average NRS of duration and severity of morning stiffness, NRS fatigue, Bath Ankylosing Spondylitis Function Index and ASAS Health Index. There are 9 additional instruments considered mandatory for disease-modifying antirheumatic drugs (DMARDs) trials: MRI activity Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joints and SPARCC spine, uveitis, inflammatory bowel disease and psoriasis assessed as recommended by ASAS, 44 swollen joint count, Maastricht Ankylosing Spondylitis Enthesitis Score, dactylitis count and modified Stoke Ankylosing Spondylitis Spinal Score. The imaging outcomes are considered mandatory to be included in at least one trial for a drug tested for properties of DMARD. Furthermore, 11 additional instruments were also endorsed by ASAS, which can be used in axSpA trials on top of the core instruments.

CONCLUSIONS: The selection of the instruments for the ASAS-OMERACT core domain set completes the update of the core outcome set for axSpA, which should be used in all trials.

Original languageEnglish
Number of pages10
JournalAnnals of the Rheumatic Diseases
Publication statusE-pub ahead of print - 9 Jun 2022


  • ankylosing
  • health care
  • outcome and process assessment
  • outcome assessment
  • spondylitis

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