title: Performance of various criteria sets in patients with inflammatory back pain of short duration; the Maastricht early spondyloarthritis clinic.
abstract: OBJECTIVE
  To describe how patients presenting with inflammatory back pain (IBP) of short duration can be classified by different sets of classification criteria for spondyloarthritis (SpA) and ankylosing spondylitis, and which clinical and imaging features are of discernible importance.
  
  
  METHODS
  68 patients with IBP of a maximum of 2 years' duration were included in the early spondyloarthritis cohort. Detailed history, clinical examination and imaging of sacroiliac joints by plain radiography and magnetic resonance imaging (MRI) were obtained. The Berlin criteria set for SpA that has a prominent place for MRI and human leucocyte antigen B27 was used to quantify the relative contribution of MRI in classifying SpA.
  
  
  RESULTS
  14 of the 68 patients had ankylosing spondylitis according to the modified New York criteria, 57 patients fulfilled the European Spondylarthropathy Study Group (ESSG) criteria for SpA, 48 patients fulfilled the Amor criteria for SpA (43 patients fulfilled both criteria sets) and 44 patients fulfilled the Berlin criteria for SpA. Only four patients did not fulfil any criteria set; 36 patients fulfilled ESSG, Amor and Berlin criteria. The 14 patients with ankylosing spondylitis fulfilled all three SpA criteria sets.
  
  
  CONCLUSIONS
  Among our selected cohort of patients with early IBP, the prevalence of SpA according to three different criteria sets is high. The ESSG criteria were the most sensitive, followed by the Amor criteria and the Berlin criteria. The modified New York criteria for ankylosing spondylitis appeared to be the most specific. In this cohort, the contribution of MRI and human leucocyte antigen B27 to purely clinical criteria in making a diagnosis of axial SpA was limited.
authors.affiliation: Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, PO Box 5800, 6202AZ Maastricht, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Heuft-Dorenbosch
authors.forename: R
authors.initials: R
authors.lastname: Landewé
authors.forename: R
authors.initials: R
authors.lastname: Weijers
authors.forename: H
authors.initials: H
authors.lastname: Houben
authors.forename: S
authors.initials: S
authors.lastname: van der Linden
authors.forename: P
authors.initials: P
authors.lastname: Jacobs
authors.forename: D
authors.initials: D
authors.lastname: van der Heijde
mesh_terms: D000465:Algorithms; D001416:Back Pain / Q000209:etiology* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D015796:HLA-B27 Antigen / Q000097:blood; D006801:Humans; D007154:Immune System Diseases / Q000150:complications; D008279:Magnetic Resonance Imaging; D008297:Male; D012017:Referral and Consultation; D012219:Rheumatology; D012680:Sensitivity and Specificity; D013131:Spine / Q000473:pathology; D025241:Spondylarthritis / Q000145:classification* / Q000150:complications / Q000276:immunology; D013167:Spondylitis, Ankylosing / Q000145:classification* / Q000150:complications / Q000276:immunology
chemical_list: D015415:Biomarkers; D015796:HLA-B27 Antigen