Background: Peripheral musculoskeletal manifestations (i.e. arthritis, dactylitis, peripheral enthesitis) can occur alongside axial disease, independently (i.e. without axial disease) or before the manifestations of the axial disease.

Recently, the ASAS-OMERACT core outcome set (COS) has been updated, and for the “peripheral manifestations domain” only two instruments were assessed for peripheral arthritis, namely the swollen joint count (SJC) with 66 and with 44 joints (SJC66 and SJC44). Although psychometric properties were comparable for both, with inadequate performance for clinical trial discrimination, both were endorsed by the ASAS members, to facilitate future assessment of their performance by promoting the standardised data collection. Finally, the SJC44 was chosen as the preferred instrument for inclusion in the COS. However, no composite score was assessed during the exercise.

Although evidence is limited, composite scores such as ASDAS, BASDAI, patient global assessment (PGA), and physician global assessment (PhGA) and DAPSA have demonstrated good performance in assessing disease activity in the pSpA population.

A recent ancillary analysis from the ASAS-perSpA study, which included patients with axSpA, PsA and pSpA, showed that composite scores including joint counts, particularly the DAS28 and DAPSA have superior discriminatory capacity better between active/inactive patients.

Aim:  To compare the psychometric properties of different measurement instruments to assess disease activity due to peripheral arthritis in patients with spondyloarthritis (either axSpA or pSpA) in clinical trials, with the aim of selecting the most adequate and best performing measurement instrument to be endorsed by ASAS.

Methods: The candidate disease activity measurement instruments to be assessed in the domain peripheral (articular) manifestations will be identified through a Systematic Literature Review (SLR). Next, following the OMERACT Filter 2.2 for the instrument selection, the psychometric properties of the candidate outcome measurement instruments will be assessed. This will include a domain match and feasibility assessment, followed by a systematic literature review on psychometric properties of selected instruments and lastly analysis in RCTs of additional psychometric properties. For the assessment of the performance of the outcome measurement instruments, both populations will be considered, axSpA and pSpA, with the expectation to obtain information separately for each disease phenotype.

Working group proposal

The results on the psychometric properties of the different measurement instruments will be presented to the Working Group in a virtual meeting. The Working Group will discuss the results and the most adequate instrument(s) and a formal proposal to be presented to the ASAS membership will be prepared.

ASAS voting

The proposal from the working group will be presented to the entire ASAS community at the annual meeting. A summary of all psychometric properties will be presented, describing all the steps leading to the proposal. Then the proposal will be presented and discussed by ASAS members, and a formal voting will be carried for the acceptance of the proposal (or alternatives discussed) by the ASAS community.

Timelines of the project: 2024-2026

Project team:

PIs:

Sofia Ramiro (Leiden, the Netherlands) and Anna Molto (France)

Steering committee:

Désirée van der Heijde (Leiden, the Netherlands)

Robert Landewé (Amsterdam, the Netherlands)

Philip Mease (Seattle, USA),

Dafne Capelusnik (Tel Aviv, Israel and Maastricht, the Netherlands)

Clementina Lopez Medina (Cordoba, Spain)

Casper Webers (Maastricht, the Netherlands)

Augusta Ortolan (Rome, Italy)

Working group:

Xenofon Baraliakos (Herne, Germany)

Wilson Bautista (Bogotá, Colombia)

Annelies Boonen (Maastricht, the Netherlands)

Philippe Carron (Ghent, Belgium)

Lianne Gensler (San Francisco, USA)

Laure Gossec (Paris, France)

Ihsane Hnanouchi (Rabat, Marroco)

Uta Kiltz (Herne, Germany)

Mitsumasa Kishimotomi (Tokyo, Japan)

Pedro Machado (London, UK)

Victoria Navarro-Compán (Madrid, Spain)

Elena Nikiphorou (London, UK)

Denis Poddubnyy (Toronto, Canada)

Alexandre Sepriano (Lisbon, Portugal)

Joachim Sieper (Berlin, Germany)

Filip van den Bosch (Ghent, Belgium)

Floris van Gaalen (Leiden, the Netherlands)

Laura Pina Vegas (Paris, France, Y-ASAS)

Gäelle Varkas (Ghent, Belgium, Y-ASAS)

Maranda van Dam (South Africa, Patient representative-ASIF)

Jo Löwe (London, UK, Patient representative-ASIF)

References:

Navarro-Compán V, Boel A, Boonen A, Mease PJ, Dougados M, et al. Instrument selection for the ASAS core outcome set for axial spondyloarthritis. Ann Rheum Dis. 2023 Jun;82(6):763-772.

Turina MC, Ramiro S, Baeten DL, Mease P, Paramarta JE, et al. A psychometric analysis of outcome measures in peripheral spondyloarthritis. Ann Rheum Dis. 2016 Jul;75(7):1302-7.

Beckers E, Been M, Webers C, Boonen A, Ten Klooster PM, et al. Performance of 3 Composite Measures for Disease Activity in Peripheral Spondyloarthritis. J Rheumatol. 2022 Mar;49(3):256-264.

López Medina C, Molto A, Capelusnik D, Carron P, Webers C, et al. Measurement Properties of Disease Activity Instruments in Peripheral Spondyloarthritis. an Analysis in the CRESPA Trial [abstract]. Arthritis Rheumatol. 2024; 76 (suppl 9).

Capelusnik D, Molto A, López Medina C, van der Heijde D, Landewé R, et al. Evaluation of Instruments Assessing Peripheral Arthritis in Spondyloarthritis: An Analysis of the ASAS-perSpA Study [abstract]. Arthritis Rheumatol. 2024; 76 (suppl 9).

Maxwell LJ, Beaton DE, Boers M, D’Agostino MA, Conaghan PG, et al. The evolution of instrument selection for inclusion in core outcome sets at OMERACT: Filter 2.2. Semin Arthritis Rheum. 2021 Dec;51(6):1320-1330.