title: Comparison on radiographic progression for 5 years between juvenile onset ankylosing spondylitis and adult onset ankylosing spondylitis: an observational study of the Korean SpondyloArthropathy Registry (OSKAR) data.
abstract: OBJECTIVE
  To evaluate differences in radiographic progression between adult-onset ankylosing spondylitis (AoAS) and juvenile-onset ankylosing spondylitis (JoAS).
  
  
  METHODS
  A total of 533 patients (418 patients with AoAS and 115 patients with JoAS) from the Observation Study of Korean spondyloArthropathy Registry (OSKAR) cohort were enrolled. All baseline OSKAR data were analysed in relation to disease onset and radiographic progression was analysed between the groups over 5 years. The modified Stoke AS Spinal Score (mSASSS) were used by two experienced radiologists. Clinical data were collected to investigate the associations between clinical factors and radiographic progression. Radiographic scores were compared using analysis of covariance model after adjusting for confounding factors.
  
  
  RESULTS
  Inter-reader reliability for baseline mSASSS was very good. Inter-reader reliability for the changes in the mSASSS was also good. A significant difference in baseline mSASSS (mean ± SD) unit was detected between the AoAS and JoAS groups (18.1±17.4 vs. 14.3±13.8, p=0.015). We assessed the change in mSASSS to confirm whether age at onset affected radiographic progression. A simple comparison revealed a significant difference between changes on the mSASSS (mean ± SEM) between the JoAS and AoAS groups (1.75±0.71 vs. 3.77±0.56, p<0.001). After adjusting for multiple comparisons, change on the mSASSS remained lower in patients with JoAS than those with AoAS (0.28±1.33 vs. 4.08±0.62, p=0.016).
  
  
  CONCLUSIONS
  Patients with JoAS had slower radiographic spinal damage progression over 5 years than those with AoAS.
authors.affiliation: Department of Rheumatology, Research Institute of Medical Sciences, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea.
authors.forename: Tae-Jong
authors.initials: TJ
authors.lastname: Kim
authors.affiliation: Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea.
authors.forename: Ji-Hui
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Orthopaedics, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea.
authors.forename: Il-Hoon
authors.initials: IH
authors.lastname: Sung
authors.affiliation: Department of Radiology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea.
authors.forename: Seunghun
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Radiology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea.
authors.forename: Yoonah
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea. thkim@hanyang.ac.kr.
authors.forename: Tae-Hwan
authors.initials: TH
authors.lastname: Kim
mesh_terms: D000328:Adult; D017668:Age of Onset; D044466:Asian People; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D016009:Chi-Square Distribution; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011859:Radiography; D012042:Registries; D012044:Regression Analysis; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging* / Q000208:ethnology; D013997:Time Factors