title: Evaluation of Assessment of Spondyloarthritis International Society classification criteria for axial spondyloarthritis in Chinese patients with chronic back pain: results of a 2-year follow-up study.
abstract: OBJECTIVE
  To evaluate the diagnotic value of the Assessment of Spondyloarthritis International Society (ASAS) classification criteria for axial spondyloarthritis (SpA) in Chinese patients with chronic back pain and without radiographic sacroiliitis in a 2-year follow-up study.
  
  
  METHODS
  Patients with chronic back pain ≥ 3 months, onset age ≤ 45 years and without radiographic sacroiliitis were enrolled, and then received 2-year follow-up. All the clinical parameters associated with SpA were recorded. The patients were followed for 2 years and the final diagnosis of axial SpA or non-SpA was confirmed by rheumatologists. Diagnostic concordance between the initial classification according to three classification criteria (ASAS criteria for axial SpA, European Spondylarthropathy Study Group (ESSG) criteria and Amor criteria) and final diagnosis was compared. Diagnostic sensitivity and specificity were compared between the two subsets of ASAS criteria (set 1: sacroiliitis plus more than one SpA feature; set 2: HLA-B27 plus two more SpA features).
  
  
  RESULTS
  One thousand and sixty-eight patients entered the study and 867 completed the 2-year follow-up (455 axial SpA and 412 non-SpA). The concordance of ASAS criteria was better than ESSG and Amor criteria. Three hundred and thirty-three patients and 335 patients were classified as axial SpA according to the ASAS set 1 and set 2 of criteria, respectively. Further, set 1 of criteria (318/333) showed higher specificity than set 2 critera (279/335) (P = 0.000).
  
  
  CONCLUSIONS
  The ASAS classification criteria for axial SpA showed good concordance in diagnosing Chinese axial SpA patients in this prospective study. Set 1 criteria involving sacroiliitis plus more than one SpA feature had better diagnosing value.
authors.affiliation: Rheumatology Department, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Lin
authors.forename: Zetao
authors.initials: Z
authors.lastname: Liao
authors.forename: Jianlin
authors.initials: J
authors.lastname: Huang
authors.forename: Ou
authors.initials: O
authors.lastname: Jin
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Li
authors.forename: Tianwang
authors.initials: T
authors.lastname: Li
authors.forename: Zaiying
authors.initials: Z
authors.lastname: Hu
authors.forename: Manlong
authors.initials: M
authors.lastname: Xu
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Pan
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhang
authors.forename: Mingcan
authors.initials: M
authors.lastname: Yang
authors.forename: Jieruo
authors.initials: J
authors.lastname: Gu
mesh_terms: D000328:Adult; D044466:Asian People; D001416:Back Pain / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D002681:China / Q000453:epidemiology; D059350:Chronic Pain / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D058566:Sacroiliitis / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D012720:Severity of Illness Index; D025241:Spondylarthritis / Q000097:blood / Q000145:classification / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: Amor criteria; Assessment of Spondyloarthritis International Society criteria; European Spondylarthropathy Study Group criteria; axial SpA; diagnostic concordance; diagnostic value