title: Construct validity and reliability of ultrasound disease activity score in assessing joint inflammation in RA: comparison with DAS-28.
abstract: OBJECTIVE
  To investigate the construct validity and reliability of US DAS compared with 28-joint DAS (DAS-28) in assessing joint inflammation and in prediction of structural damage in patients with RA.
  
  
  METHODS
  Ninety patients with active RA were prospectively recruited and followed up during the 6 months of treatment. The patients underwent clinical, laboratory and X-ray assessment, along with blinded power Doppler US (PDUS) and grey-scale (GS) US (GSUS) examination at baseline and 6 months. A subgroup of 25/90 randomly assigned patients underwent MRI examination of their hands at baseline. A PDUS examination of 22 joints and GSUS examination for effusion/hypertrophy (E/H) of 28 joints were performed by two independent examiners, blinded to clinical findings. E/H was qualitatively assessed as absent or present, and PD signal was semi-quantitatively graded from 0 to 3. PDUS score for synovitis in 22 joints and GS score for E/H in 28 joints were included in US DAS calculation. Clinical scoring, PDUS and GSUS inter-observer reliability were evaluated.
  
  
  RESULTS
  Strong correlation was found between US DAS and standard assessment of disease activity such as the DAS-28, ESR and CRP levels. Correlation between US DAS and patients' and physicians' visual analogue scale of activity was moderate, whereas correlations of US DAS with Health Assessment Questionnaire - Disability Index (HAQ-DI) and Short Form 36 Health Survey (SF-36) were weak to moderate. US DAS correlated with X-ray, MRI and US parameters and rates of joint damage.
  
  
  CONCLUSIONS
  US DAS better anticipated future joint damage than standard DAS-28.
authors.affiliation: Institute of Rheumatology, University of Belgrade Medical School, Resavska 69, 11000 Belgrade, Serbia. nemanjadamjanov@yahoo.com
authors.forename: Nemanja
authors.initials: N
authors.lastname: Damjanov
authors.forename: Goran
authors.initials: G
authors.lastname: Radunovic
authors.forename: Slavica
authors.initials: S
authors.lastname: Prodanovic
authors.forename: Vesna
authors.initials: V
authors.lastname: Vukovic
authors.forename: Vera
authors.initials: V
authors.lastname: Milic
authors.forename: Katarina
authors.initials: K
authors.lastname: Simic Pasalic
authors.forename: Dragoslav
authors.initials: D
authors.lastname: Jablanovic
authors.forename: Srdan
authors.initials: S
authors.lastname: Seric
authors.forename: Sanja
authors.initials: S
authors.lastname: Milutinovic
authors.forename: Nikola
authors.initials: N
authors.lastname: Gavrilov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000000981:diagnostic imaging*; D018450:Disease Progression; D004812:Epidemiologic Methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008662:Metacarpophalangeal Joint / Q000473:pathology; D008875:Middle Aged; D015588:Observer Variation; D010808:Physical Examination / Q000379:methods; D011379:Prognosis; D012720:Severity of Illness Index; D013585:Synovitis / Q000175:diagnosis / Q000000981:diagnostic imaging; D018608:Ultrasonography, Doppler / Q000379:methods; D014955:Wrist Joint / Q000473:pathology