title: Defining erosive disease typical of RA in the light of the ACR/EULAR 2010 criteria for rheumatoid arthritis; results of the data driven phase.
abstract: BACKGROUND
  According to the 2010 criteria, rheumatoid arthritis (RA) can be classified in the presence of ≥6 points on the criteria or 'typical' erosive disease. RA-specific erosiveness however has not been defined yet. This study reports the results of the data driven phase of a European League Against Rheumatism (EULAR) taskforce aiming to define RA-specific erosiveness.
  
  
  METHODS
  Baseline radiographs of hands and feet of 980 Dutch and 811 French early arthritis patients were studied on the number and site of erosive joints. Test characteristics were determined, with the outcome measures being initiation of methotrexate (MTX) therapy or any disease modifying antirheumatic drug (DMARD) therapy within the first year of disease and arthritis persistency over 5 years. Analyses were repeated in the patients with <6 points on the American College of Rheumatology/EULAR 2010 criteria.
  
  
  RESULTS
  In both cohorts comparable test characteristics were observed for the outcomes MTX therapy, any DMARD therapy and arthritis persistency. Test characteristics were not influenced by the site of erosiveness. The specificity observed was >50% for ≥1 erosive joint, >80% for ≥3 erosive joints and >90% for ≥5 erosive joints. When analysing the patients not fulfilling the 2010 criteria (n=308 and 149), specificity was >60% for ≥1 erosive joint, >90% for ≥3 erosive joints and >95% for ≥5 erosive joints. Few of these patients fulfilled the radiological criterion; 27-36 patients had ≥3 erosive joints and 13-14 patients had ≥5 erosive joints.
  
  
  CONCLUSIONS
  RA-specific erosiveness can be defined with high specificity at several cut-offs for the number of erosive joints in two independent cohorts with multiple different outcomes. The final radiological criterion will be established in the next phase.
authors: Correspondence to Dr Annette H M van der Helm-van Mil, Department of Rheumatology, Leiden University Medical Center, P.O. Box 9600, Leiden 2300RC, The Netherlands.
authors: Rachel
authors: R
authors: Knevel
authors: Cédric
authors: C
authors: Lukas
authors: Désirée
authors: D
authors: van der Heijde
authors: Nathalie
authors: N
authors: Rincheval
authors: Bernard
authors: B
authors: Combe
authors: Annette H M
authors: AH
authors: van der Helm-van Mil
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000145:classification* / Q000000981:diagnostic imaging* / Q000188:drug therapy; D001175:Arthrography / Q000592:standards*; D003953:Diagnosis-Related Groups / Q000592:standards; D018450:Disease Progression; D005060:Europe; D005260:Female; D006801:Humans; D007596:Joints / Q000473:pathology*; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012219:Rheumatology / Q000592:standards; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D008727:Methotrexate