RESEARCH - Reliability of dermoscopy in the assessment of patients with Raynaud's phenomenon

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Rheumatology Advance Access published online on December 22, 2009

Rheumatology, doi:10.1093/rheumatology/kep408

Reliability of dermoscopy in the assessment of patients with Raynaud’s

phenomenon

Tonia L. 1, 2, K. Murray3, Ingrid

Helbling4 and Ariane L. Herrick3

1Salford Royal NHS Foundation Trust, Salford, 2Health Methodology

Group, School of Community Base Medicine, University of Manchester,

Manchester, 3University of Manchester, Manchester Academic Health

Science Centre, Salford Royal NHS Foundation Trust, Salford and

4Department of Dermatology, Chesterfield Royal Hospital NHS Foundation

Trust, Chesterfield, UK.

Abstract

Objective. Few rheumatologists have access to wide field or video

capillaroscopy (abnormal capillaries being highly predictive of CTD),

and a key question is whether they should, therefore, purchase a

dermatoscope. The aim of this study was to estimate the inter- and

intra-observer variability of dermoscopy (magnification 10x) among

rheumatologists with little or no experience of the technique. Good

reliability is a necessary prerequisite for a test to be a valid

clinical or research tool.

Methods. Dermoscopy was performed in all 10 nail folds from 16

subjects with a range of capillary normality/abnormality. The 160 nail

fold images thus acquired were made into two PowerPoint presentations,

each of 80 images with 16 duplicate slides. Each participating

rheumatologist graded one of the sets of 96 images, grading scale

(0–3): normal, mildly abnormal/‘suspicious’, definitely abnormal,

grossly abnormal capillaries or ‘unclassifiable’ when capillaries

could not be adequately identified. Data from both presentations were

pooled for analysis.

Results. Twenty-eight rheumatologists participated in the study. For

the decision as to whether an image could be classified or not, the

inter- and intra-observer -coefficients were 0.59 (95% CI 0.51, 0.67)

and 0.63 (95% CI 0.45, 0.74), respectively. Conditional on being able

to classify, the intra-class correlation coefficient for inter- and

intra-observer reliability was 0.72 (95% CI 0.66, 0.77) and 0.85 (95%

CI 0.82, 0.92), respectively.

Conclusions. Inter- and intra-observer reliability were good,

suggesting that with little training, dermoscopy is likely to be a

useful technique to identify capillary distortions/underlying CTD.

http://rheumatology.oxfordjournals.org/cgi/content/abstract/kep408v1?papetoc

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