Comparative analysis of instruments measuring peripheral arthritis activity in Spondyloarthritis: a measurement properties study in 13 RCTs

RMD Open, vol. 12, pp. e007207

Abstract

OBJECTIVES: Using randomised controlled trial (RCT) data, this study evaluated the measurement properties of selected instruments to assess peripheral arthritis in axial and peripheral spondyloarthritis (axSpA/pSpA) and to inform selection of the best-performing instrument. METHODS: Eligible studies were RCTs in axSpA or pSpA with individual patient data available to calculate Patient Global Assessment (PGA), swollen/tender joint counts (44 or 66/68 joints), C reactive protein, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Axial Spondyloarthritis Disease Activity Score, Disease Activity Index for Psoriatic Arthritis/Disease Activity in Psoriatic Arthritis with 44 joint count (DAPSA44) and 44-joint Disease Activity Score at baseline and timing of primary endpoint. In axSpA, analyses were restricted to patients with peripheral arthritis at baseline. Measurement properties assessed included construct validity, test-retest reliability, longitudinal construct validity, trial discrimination and thresholds of meaning. Risk of bias (RoB) was evaluated and evidence was synthesised using Outcome Measures in Rheumatology-based GREEN/AMBER/RED ratings (low/uncertain/high RoB and good/adequate/poor performance, respectively). RESULTS: 13 RCTs were included (10 axSpA and 3 pSpA). In axSpA trials, 25-51% of patients had peripheral arthritis at baseline (median swollen joint count of 44 joints (SJC44) across studies: 2-3); in pSpA trials, median SJC44 ranged 2-5. In axSpA, construct validity and thresholds of meaning were rated AMBER/GREEN for all instruments, while test-retest reliability was RED only for PGA. Responsiveness was consistently GREEN. Clinical trial discrimination was RED for single-item instruments but consistently GREEN for composite scores. In pSpA, most instruments showed AMBER/GREEN performance, although SJC44 demonstrated RED discrimination. CONCLUSIONS: This study provides the first comprehensive, trial-based evaluation of measurement properties for instruments assessing peripheral arthritis activity in axSpA and pSpA. Composite scores, such as BASDAI, ASDAS and DAPSA44, generally demonstrated more robust performance than single-item instruments, expanding the evidence base for the final instrument-selection phase.

Authors 9

1. Dafne Capelusnik

   Tel Aviv Sourasky Medical Center · Maastricht University · Care and Public Health Research Institute

   Affiliation as printed

   Care and Public Health Research Institute (CAPHRI), Maastricht University, Maastricht, The Netherlands

   Department of Rheumatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel

2. Clementina López‐Medina

   Instituto Maimónides de Investigación Biomédica de Córdoba · Hospital Universitario Reina Sofía · University of Córdoba

   Affiliation as printed

   Maimonides Biomedical Research Institute of Cordoba, University of Cordoba, Córdoba, Spain

   Rheumatology, Reina Sofia University Hospital, Cordoba, Spain

3. Casper Webers

   Maastricht University Medical Centre · Maastricht University · Care and Public Health Research Institute

   Affiliation as printed

   Department of Medicine, Division of Rheumatology, Maastricht University Medical Centre, Maastricht, The Netherlands

   Public Health Research Institute (CAPHRI), Maastricht University, Maastricht, The Netherlands

4. Augusta Ortolan

   Università Cattolica del Sacro Cuore · Agostino Gemelli University Polyclinic

   Affiliation as printed

   Department of Rheumatology, Fondazione Policlinico Universitario Agostino Gemelli IRCSS, Catholic University of the Sacred Heart, Rome, Italy

5. Désirée M F M van der Heijde Aachen Department of Rheumatology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands

6. Robert Landewé

   Zuyderland Medisch Centrum · Amsterdam University Medical Centers · University of Amsterdam

   Affiliation as printed

   Department of Rheumatology & Clinical Immunology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands

   Department of Rheumatology, Zuyderland Medical Center, Heerlen, The Netherlands

7. Philip J. Mease

   University of Washington · Swedish Medical Center

   Affiliation as printed

   Department of Rheumatology, Providence Swedish Medical Center; and University of Washington, Seattle, Washington, USA

8. Anna Moltó

   Inserm · Université Paris Cité · Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement · Université Sorbonne Paris Nord · Hôpital Bichat-Claude-Bernard · Centre de Recherche Épidémiologie et Statistique

   Affiliation as printed

   Rheumatology Department, Bichat Hospital, Paris, France

   Université Paris Cité and Université Sorbonne Paris Nord, INSERM, INRAE, Centre for Research in Epidemiology and Statistics, Paris, France

9. Josef S Smolen Aachen Department of Rheumatology, Leiden University Medical Center

   Leiden University Medical Center · Zuyderland Medisch Centrum

   Affiliation as printed

   Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands

   Department of Rheumatology, Zuyderland Medical Center, Heerlen, The Netherlands