Reliability of the qualitative and semiquantitative nailfold videocapillaroscopy assessment in a systemic sclerosis cohort: a two-centre study.
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.
Smith
Vanessa
V
Department of Rheumatology, Ghent University Hospital, 0K12-IB, De Pintelaan 185, Ghent B-9000, Belgium. vanessa.smith@ugent.be
Pizzorni
Carmen
C
De Keyser
Filip
F
Decuman
Saskia
S
Van Praet
Jens T
JT
Deschepper
Ellen
E
Sulli
Alberto
A
Cutolo
Maurizio
M
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