title: Increased type I collagen degradation correlates with disease severity in rheumatoid arthritis.
abstract: OBJECTIVE
  To assess the extent and clinical significance of type I collagen degradation in rheumatoid arthritis (RA).
  
  
  METHODS
  Serum samples from 90 consecutive patients with RA from a cross-sectional population based study and 90 age- and sex-matched controls were analysed with the new assay of cross-linked carboxyterminal telopeptide of type I collagen (ICTP).
  
  
  RESULTS
  Patients with RA had significantly higher concentrations of ICTP than the controls. ICTP correlated strongly with measures of impairment in RA, such as the erosive state of joint disease (ES) (r = 0.57, p < 0.001) and Keitel function test (KFT) (r = 0.49, p < 0.001), and more weakly with various disease activity markers. When erythrocyte sedimentation rate (ESR), ES or KFT were used as indicators of disease severity among the patients with disease duration over five years, ICTP distinguished the more serious RA from milder cases.
  
  
  CONCLUSIONS
  Elevated serum concentrations of ICTP are common in RA and are associated with signs of aggressive disease.
authors.affiliation: Päivärinne Hospital, Muhos, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Hakala
authors.forename: L
authors.initials: L
authors.lastname: Risteli
authors.forename: J
authors.initials: J
authors.lastname: Manelius
authors.forename: P
authors.initials: P
authors.lastname: Nieminen
authors.forename: J
authors.initials: J
authors.lastname: Risteli
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000473:pathology / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D003094:Collagen / Q000097:blood* / Q000737:chemistry; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007596:Joints / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood*; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D003094:Collagen