title: Reliability of the qualitative and semiquantitative nailfold videocapillaroscopy assessment in a systemic sclerosis cohort: a two-centre study.
abstract: OBJECTIVE
  Investigation of the reliability of the qualitative and semiquantitative scoring of nailfold videocapillaroscopy (NVC) assessment between two raters in a systemic sclerosis (SSc) cohort.
  
  
  METHODS
  Two raters from different centres blindly assessed the NVC images of 71 consecutive patients with SSc qualitatively as belonging to the scleroderma spectrum (SDS) category ('early', 'active', 'late' scleroderma pattern or 'scleroderma-like' pattern) or to the 'normal' category and semiquantitatively by calculating the mean score for capillary loss, giant capillaries, microhaemorrhages and capillary ramifications. Inter-rater/intrarater agreement was assessed by calculation of the proportion of agreement and by kappa coefficients. Rater agreement of mean score values of hallmark parameters was assessed by intraclass correlation coefficients.
  
  
  RESULTS
  The inter-rater/intrarater proportion of agreement to qualitatively assess an image as belonging to the SDS category or not was 90% and 96%, whereas the agreement to distinguish between only 'early', 'active' and 'late' scleroderma NVC patterns was 62% and 81%. The agreement of the semiquantitative scoring, as assessed by intraclass correlation coefficient, was 0.96 and 0.95 for capillary loss, 0.84 and 0.95 for giant capillaries, 0.90 and 0.95 for microhaemorrhages and 0.64 and 0.95 for capillary ramifications.
  
  
  CONCLUSIONS
  This is the first study to demonstrate reliability of the qualitative and semiquantitative NVC assessment in an SSc cohort between raters at different centres. Reliability of NVC assessment is essential for use of this tool in multicentre SSc trials.
authors.affiliation: Department of Rheumatology, Ghent University Hospital, 0K12-IB, De Pintelaan 185, Ghent B-9000, Belgium. vanessa.smith@ugent.be
authors.forename: Vanessa
authors.initials: V
authors.lastname: Smith
authors.forename: Carmen
authors.initials: C
authors.lastname: Pizzorni
authors.forename: Filip
authors.initials: F
authors.lastname: De Keyser
authors.forename: Saskia
authors.initials: S
authors.lastname: Decuman
authors.forename: Jens T
authors.initials: JT
authors.lastname: Van Praet
authors.forename: Ellen
authors.initials: E
authors.lastname: Deschepper
authors.forename: Alberto
authors.initials: A
authors.lastname: Sulli
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cutolo
mesh_terms: D000328:Adult; D000368:Aged; D002196:Capillaries / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D020678:Microscopic Angioscopy / Q000379:methods; D008875:Middle Aged; D009262:Nails / Q000098:blood supply*; D015588:Observer Variation; D015203:Reproducibility of Results; D012595:Scleroderma, Systemic / Q000175:diagnosis*; D014741:Video Recording / Q000379:methods