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Reliability of the qualitative and semiquantitative nailfold videocapillaroscopy assessment in a systemic sclerosis cohort: a two-centre study
  1. Vanessa Smith1,
  2. Carmen Pizzorni2,
  3. Filip De Keyser1,
  4. Saskia Decuman1,
  5. Jens T Van Praet1,
  6. Ellen Deschepper3,
  7. Alberto Sulli2,
  8. Maurizio Cutolo2
  1. 1Department of Rheumatology, Ghent University Hospital, Ghent, Belgium
  2. 2Research Laboratory and Academic Unit of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Genova, Italy
  3. 3Biostatistics Unit, Ghent University Hospital, Ghent, Belgium
  1. Correspondence to Dr Vanessa Smith, Department of Rheumatology, Ghent University Hospital, 0K 12-lB, De Pintelaan 185, Ghent B-9000, Belgium; vanessa.smith{at}ugent.be

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 κ 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.

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Footnotes

  • VS, CP and FDK contributed equally to this work.

  • Funding JTVP is supported by a research grant from the Fund for Scientific Research-Flanders. SD is supported by a grant from the ‘Rotary – National Association to support Disabled People’.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the ethical committee of Ghent University. All patients signed informed consent.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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