title: Association of baseline levels of markers of bone and cartilage degradation with long-term progression of joint damage in patients with early rheumatoid arthritis: the COBRA study.
abstract: OBJECTIVE
  The known risk factors for radiologic progression in rheumatoid arthritis (RA) are not optimally discriminative in patients with early disease who do not have evidence of radiologic damage. We sought to determine whether urinary C-terminal crosslinking telopeptide of type I (CTX-I) and type II (CTX-II) collagen (markers of bone and cartilage destruction, respectively) are associated with long-term radiologic progression in patients with early RA.
  
  
  METHODS
  This was a prospective study of 110 patients with early RA who were participating in the COBRA (Combinatietherapie Bij Reumatoïde Artritis) clinical trial and followup study, a randomized controlled trial comparing the efficacy of oral pulse prednisolone, methotrexate, plus sulfasalazine with sulfasalazine alone. We investigated the relationship between baseline levels of urinary CTX-I and CTX-II and the mean annual progression of joint destruction over a median of 4 years, as measured by changes in the modified Sharp score (average of 2 independent readers).
  
  
  RESULTS
  In multivariate logistic regression analysis, baseline urinary CTX-I and CTX-II levels in the highest tertile were the strongest predictors of radiologic progression (Sharp score increase >2 units/year; odds ratio 7.9 and 11.2, respectively), independently of treatment group, erythrocyte sedimentation rate (ESR), Disease Activity Score in 28 joints, rheumatoid factor (RF), and baseline joint damage (Sharp score). The likelihood ratios for a positive test were 3.8 and 8.0 for CTX-I and CTX-II, respectively, which compared favorably with the likelihood ratios for the ESR (3.0), baseline joint damage (1.6), and RF (1.8). When patients were grouped according to the presence (Sharp score >/=4, n = 49) and absence (Sharp score <4, n = 61) of joint damage at baseline, CTX-I and CTX-II levels were predictive only in those without baseline joint damage (odds ratio 14.9 and 25.7, respectively).
  
  
  CONCLUSIONS
  High baseline levels of urinary CTX-I and CTX-II independently predict an increased risk of radiologic progression over 4 years in patients with early RA, especially those without radiologic joint damage. Urinary CTX-I and CTX-II may be useful for identifying individual RA patients at high risk of progression very early in the disease, before erosions can be detected radiographically. Such patients may be in special need of treatments that inhibit bone and cartilage degradation.
authors.affiliation: INSERM Research Unit 403, and Synarc, Lyon, France. patrick.garnero@synarc.com
authors.forename: Patrick
authors.initials: P
authors.lastname: Garnero
authors.forename: Robert
authors.initials: R
authors.lastname: Landewé
authors.forename: Maarten
authors.initials: M
authors.lastname: Boers
authors.forename: Arco
authors.initials: A
authors.lastname: Verhoeven
authors.forename: Sjef
authors.initials: S
authors.lastname: Van Der Linden
authors.forename: Stephan
authors.initials: S
authors.lastname: Christgau
authors.forename: Désirée
authors.initials: D
authors.lastname: Van Der Heijde
authors.forename: Annelies
authors.initials: A
authors.lastname: Boonen
authors.forename: Piet
authors.initials: P
authors.lastname: Geusens
mesh_terms: D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000652:urine*; D015415:Biomarkers / Q000652:urine*; D001799:Blood Sedimentation; D024042:Collagen Type I / Q000652:urine*; D024043:Collagen Type II / Q000652:urine*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage; D008875:Middle Aged; D010446:Peptide Fragments / Q000652:urine; D011239:Prednisolone / Q000008:administration & dosage; D011446:Prospective Studies; D011859:Radiography; D012680:Sensitivity and Specificity; D012460:Sulfasalazine / Q000008:administration & dosage
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D024043:Collagen Type II; D010446:Peptide Fragments; D012460:Sulfasalazine; D011239:Prednisolone; D008727:Methotrexate