title: Classification of axial SpA based on positive imaging (radiographs and/or MRI of the sacroiliac joints) by local rheumatologists or radiologists versus central trained readers in the DESIR cohort.
abstract: OBJECTIVE
  Investigating changes in patient classification (ASAS (Assessment of SpondyloArthritis international Society) axSpA criteria) based on evaluation of images of the sacro-iliac joints (MRI-SI and X-SI) by local and central readers.
  
  
  METHODS
  The DESIR cohort included patients with inflammatory back pain (IBP; ≥3 months, but <3 years), suggestive of axSpA. Local radiologists/rheumatologists (local-reading) and two central readers (central-reading) evaluated baseline images. Agreement regarding positive MRI (pos-MRI) between central readers and between local-reading and central-reading was calculated (κs). Number of patients classified differently (ASAS criteria) by using local-reading instead of central-reading was calculated.
  
  
  RESULTS
  Inter-reader agreement between the two central readers and between local-reading and central-reading was substantial (κ=0.73 and κ=0.70, respectively). In 89/663 MRI-SIs (13.4%) local-reading and central-reading disagreed; 38/223 patients (17.0%) with pos-MRI (local-reading) were negative by central-reading; 51/440 patients (11.6%) with neg-MRI (local-reading) were positive by central-reading.In 163/582 patients eligible for applying ASAS criteria (28.0%), local-reading and central-reading disagreed on positive imaging (MRI-SI and/or X-SI; κ=0.68). In 46/582 patients (7.9%) a different evaluation resulted in a different classification; 18/582 patients (3.1%) classified no-SpA (central-reading) were axSpA by local-reading; 28/582 patients (4.8%) classified axSpA (central-reading) were no-SpA by local-reading. Among axSpA patients (central-reading), 16/419 patients (3.8%) fulfilling imaging-arm by central-reading fulfilled clinical-arm by local-reading; 29/419 patients (6.9%) fulfilling clinical-arm by central-reading fulfilled also imaging-arm by local-reading.
  
  
  CONCLUSIONS
  In patients with recent onset IBP, trained readers and local rheumatologists/radiologists agree well on recognising a pos-MRI. While disagreeing in 28% of the patients on positive imaging (MRI-SI and/or X-SI), classification of only 7.9% of the patients changed based on a different evaluation of images, showing the ASAS axSpA criteria's robustness.
authors: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Rosaline
authors: R
authors: van den Berg
authors: Radiology Department, Clinique Hartmann, Neuilly Sur Seine, France.
authors: Grégory
authors: G
authors: Lenczner
authors: Radiology B Department, Paris Descartes University, Cochin Hospital, Paris, France.
authors: Fabrice
authors: F
authors: Thévenin
authors: Department of Rheumatology, AP-HP, Chenevier-Mondor Hospital, Créteil, France EA4393 Laboratoire d'Investigation Clinique (LIC), Université Paris Est Créteil, Créteil, France.
authors: Pascal
authors: P
authors: Claudepierre
authors: Radiology B Department, Paris Descartes University, Cochin Hospital, Paris, France.
authors: Antoine
authors: A
authors: Feydy
authors: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Monique
authors: M
authors: Reijnierse
authors: Rheumatology Unit, Hôpital de la Cavale Blanche, CHU Brest and EA 2216, Université de Bretagne Occidentale, Brest, France.
authors: Alain
authors: A
authors: Saraux
authors: Department of Radiology, Hôpital Henri Mondor, Créteil, France.
authors: Alain
authors: A
authors: Rahmouni
authors: Paris Descartes University Department of Rheumatology, Hôpital Cochin, Assistance Publique-hôpitaux de Paris, Paris, France INSERM (U1153): Clinical Epidemiology and Biostatistics, PRES Sorbonne Paris-Cité, Paris, France.
authors: Maxime
authors: M
authors: Dougados
authors: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Désirée
authors: D
authors: van der Heijde
mesh_terms: D000293:Adolescent; D000328:Adult; D001416:Back Pain / Q000209:etiology / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011871:Radiology / Q000592:standards*; D012219:Rheumatology / Q000592:standards*; D012446:Sacroiliac Joint / Q000473:pathology*; D058566:Sacroiliitis / Q000150:complications / Q000473:pathology*; D012720:Severity of Illness Index; D025242:Spondylarthropathies / Q000150:complications / Q000473:pathology; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000473:pathology*; D055815:Young Adult
keywords: Ankylosing Spondylitis; Magnetic Resonance Imaging; Spondyloarthritis