title: The value of ultrasonography in predicting arthritis in auto-antibody positive arthralgia patients: a prospective cohort study.
abstract: BACKGROUND
  Ultrasonography (US) has better sensitivity than clinical evaluation for the detection of synovitis in early rheumatoid arthritis (RA). Patients presenting with arthralgia and a positive anti-citrullinated protein antibodies (ACPA) and/or Rheumatoid Factor (IgM-RF) status are at risk for developing RA. In the present study, US utility and predictive properties in arthralgia patients at risk for the development of arthritis were studied.
  
  
  METHODS
  192 arthralgia patients with ACPA and/or IgM-RF were included. Absence of clinical arthritis was confirmed by two physicians. US was performed by one of two trained radiologists of any painful joint, and of adjacent and contralateral joints. Joint effusion, synovitis and power Doppler (PD) signal in the synovial membrane of the joints and tenosynovitis adjacent to the joint were evaluated and classified on a 4-grade semi-quantitative scale. Grade 2-3 joint effusion, synovitis, tenosynovitis and grade 1-3 Power Doppler signal were classified as abnormal.
  
  
  RESULTS
  Forty-five patients (23%) developed arthritis after a mean of 11 months. Inter-observer reliability for synovitis and PD was moderate (kappa 0.46, and 0.56, respectively) and for joint effusion low (kappa 0.23). The prevalence of tenosynovitis was too low to calculate representative kappa values. At joint level, a significant association was found between US abnormalities and arthritis development in that joint for joint effusion, synovitis and PD. At patient level, a trend was seen towards more arthritis development in patients who had US abnormalities for joint effusion, synovitis, PD and tenosynovitis.
  
  
  CONCLUSIONS
  US abnormalities were associated with arthritis development at joint level, although this association did not reach statistical significance at patient level. US could potentially be used as a diagnostic tool for subclinical arthritis in seropositive arthralgia patients. However, further research is necessary to improve test characteristics.
authors.affiliation: Rheumatology, Jan van Breemen Institute, Dr Jan van Breemenstraat 2, 1056 AB, Amsterdam, The Netherlands. l.vd.stadt@janvanbreemen.nl
authors.forename: Lotte A
authors.initials: LA
authors.lastname: van de Stadt
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Bos
authors.forename: Marlies
authors.initials: M
authors.lastname: Meursinge Reynders
authors.forename: Helen
authors.initials: H
authors.lastname: Wieringa
authors.forename: Franktien
authors.initials: F
authors.lastname: Turkstra
authors.forename: Conny J
authors.initials: CJ
authors.lastname: van der Laken
authors.forename: Dirkjan
authors.initials: D
authors.lastname: van Schaardenburg
mesh_terms: D000328:Adult; D018771:Arthralgia / Q000097:blood / Q000000981:diagnostic imaging* / Q000276:immunology*; D001168:Arthritis / Q000453:epidemiology*; D001323:Autoantibodies / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010456:Peptides, Cyclic / Q000276:immunology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012217:Rheumatoid Factor / Q000097:blood*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler
chemical_list: D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor