title: Validation of a prediction rule for development of rheumatoid arthritis in patients with early undifferentiated arthritis.
abstract: OBJECTIVE
  To validate a model which predicts progression from undifferentiated arthritis (UA) to RA, in a Canadian UA cohort.
  
  
  METHODS
  The prediction rule, comprising variables which are scored from 0 to 13, with higher scores reflecting an increased risk of RA, was applied to baseline characteristics of all patients with UA. Progression to RA was determined at 6 months.
  
  
  RESULTS
  105 patients were identified. By 6 months, 80 (76%) had developed RA while 25 (24%) had developed another diagnosis. Number of tender and swollen joints, rheumatoid factor positivity, anti-cyclic citrullinated peptide positivity, poor functional status and high disease activity were associated with development of RA (p<0.01). Median prediction score was 8.0 for progressors, 5.0 for non-progressors. With these cut-off points, 18 (72%) patients with scores < or =5 did not develop RA, while 35 (97%) with scores > or =8 did develop RA.
  
  
  CONCLUSIONS
  High scores in our cohort predicted those who progressed to RA by 6 months. Baseline scores > or =8 corresponded with higher rates of progression.
authors.affiliation: Division of Rheumatology, Mount Sinai Hospital, University of Toronto, Wolf and Lebovic Building, 60 Murray Street, Box 11, 2nd floor, Toronto, Ontario M5T 3L9, Canada. bindee.kuriya@gmail.com
authors.forename: B
authors.initials: B
authors.lastname: Kuriya
authors.forename: C K
authors.initials: CK
authors.lastname: Cheng
authors.forename: H M
authors.initials: HM
authors.lastname: Chen
authors.forename: V P
authors.initials: VP
authors.lastname: Bykerk
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001168:Arthritis / Q000175:diagnosis* / Q000473:pathology; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000473:pathology; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers / Q000097:blood; D018450:Disease Progression; D042241:Early Diagnosis; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology; D011379:Prognosis; D012217:Rheumatoid Factor / Q000097:blood
chemical_list: D018501:Antirheumatic Agents; D001323:Autoantibodies; D015415:Biomarkers; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor