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An Assessment in SpondyloArthritis International Society (ASAS)-endorsed definition of clinically important worsening in axial spondyloarthritis based on ASDAS
  1. Anna Molto1,2,
  2. Laure Gossec3,4,5,
  3. Bhowmik Meghnathi1,6,
  4. Robert B M Landewé7,8,
  5. Désirée van der Heijde9,
  6. Pamir Atagunduz10,
  7. Bassel Kamal Elzorkany11,
  8. Nurullah Akkoc12,
  9. Uta Kiltz13,
  10. Jieruo Gu14,
  11. James Cheng Chung Wei15,16,17,
  12. Maxime Dougados1,2,6
  13. on behalf of the ASAS-FLARE study group
    1. 1 APHP, Rheumatology B Department, Cochin Hospital, Paris, France
    2. 2 Inserm Unit INSERM (U1153): Clinical Epidemiology and Biostatistics, PRES Sorbonne Paris-Cité, Paris, France
    3. 3 UPMC, Sorbonne Universités, Paris, France
    4. 4 Department of Rheumatology, AP-HP, Pitié Salpêtrière Hospital, Paris, France
    5. 5 GRC-UPMC 08 (EEMOIS), Institut Pierre Louis d’Epidémiologie et de Santé Publique, Paris, France
    6. 6 Medicine Faculty, Paris Descartes University, Paris, France
    7. 7 Department of Clinical Immunology & Rheumatology, Amsterdam Rheumatology Center, Amsterdam, The Netherlands
    8. 8 Zuyderland Medical Center, Heerlen, The Netherlands
    9. 9 Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands
    10. 10 Department of Rheumatology, Faculty of Medicine, Marmara University, Istanbul, Turkey
    11. 11 Rheumatology Department, Cairo University, Cairo, Egypt
    12. 12 Internal Medicine/Division of Rheumatology, Dokuz Eylul university school of medicine, Izmir, Turkey
    13. 13 Rheumazentrum Ruhrgebiet, Herne, Germany
    14. 14 Department of Rheumatology and Immunology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
    15. 15 Division of Allergy, Immunology and Rheumatology, Chung Shan Medical University Hospital, Taichung, China
    16. 16 Institute of Medicine, Chung Shan Medical University, Taichung, China
    17. 17 Graduate Institute of Integrated Medicine, China Medical University, Taichung, China
    1. Correspondence to Dr Anna Molto, 27 rue du Faubourg Saint Jacques, 75014, Paris, France; anna.molto{at}


    Introduction In a previous phase, 12 draft definitions for clinically important worsening in axial spondyloarthritis (axSpA) were selected, of which 3 were based on absolute changes in Ankylosing Spondylitis Disease Activity Score (ASDAS)-CRP (ASDAS). The objective here was to select the best cut-off for ASDAS for clinically important worsening in axSpA for use in clinical trials and observational studies.

    Methods An international longitudinal prospective study evaluating stable patients with axSpA was conducted. Data necessary to calculate ASDAS were collected at two consecutive visits (spaced 7 days to 6 months). Sensitivity and specificity of the three cut-offs for change in ASDAS were tested against the patient’s subjective assessment of worsening as the external standard (ie, the patient reporting that he had worsened and felt a need for treatment intensification). Final selection was made by a consensus and voting procedure among Assessment of SpondyloArthritis International Society (ASAS) members.

    Results In total, 1169 patients with axSpA were analysed: 64.8% were male and had a mean age of 41.7 (SD 12.4) years. At the second visit, 127 (10.9%) patients judged their situation as worsened.

    Sensitivity and specificity for an increase of at least 0.6, 0.9 and 1.1 ASDAS points to detect patient-reported worsening were 0.55 (Se) and 0.91 (Sp), 0.38 (Se) and 0.96 (Sp), and 0.33 (Se) and 0.98 (Sp), respectively. The ASAS consensus was to define clinically important worsening as an increase in ASDAS of at least 0.9 points.

    Conclusion This data-driven ASAS consensus process resulted in an ASDAS-based cut-off value defining clinically important worsening in axSpA for use in trials.

    • Spondyloarthritis
    • Outcomes Research
    • Disease Activity

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    • Handling editor Tore K Kvien

    • Contributors AM, LG, MD, RBML, DvdH, conception, design, analysis and interpretation of data. AM: drafting the article. All authors critically revised the manuscript for important intellectual content. All authors read and approved the final manuscript.

    • Funding This study was funded by an ASAS grant.

    • Competing interests None declared.

    • Patient consent Obtained.

    • Ethics approval Ethical approval was locally obtained in all participating centres.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data sharing statement The data sets generated and/or analysed during the current study are not publicly available due to consent restrictions. Programming codes used for statistical analysis during the current study are available from the corresponding author upon reasonable request.

    • Collaborators A Molto, L Gossec, B Meghnathi, R B M Landewé, D van der Heijde, P Atagunduz, B K Elzorkany, N Akkoc, U Kiltz, J Gu, J C C Wei, M Dougados, S Pandya, V Navarro, I Gaydukova, P Geher, A Spoorenberg, S Aydin, F Pimentel, M Kishimoto, F van Gallen, E Collantes-Estevez, R Schiotis, H Marzo-Ortega, B O’Shea, C Ramos-Remus, M Magrey.