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 ramifi cations. Inter-rater/intrarater agreement was assessed by calculation of the proportion of agreement and by κ coeffi cients. Rater agreement of mean score values of hallmark parameters was assessed by intraclass correlation coeffi cients. 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 coeffi cient, 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 ramifi cations. Conclusions This is the fi rst 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.

Effects of Longterm Treatment with Bosentan and Iloprost on Nailfold Absolute Capillary Number, Fingertip Blood Perfusion, and Clinical Status in Systemic Sclerosis

“…Because capillary density observed at NVC is usually presented as a percentage or a ratio as part of the semiquantitative scoring system, in our present study the absolute capillary number/mm was evaluated to increase the sensitivity 15,21,22 .…”

“…Capillary absolute number was obtained counting all capillary loops, observable in the first row, in 1 mm per field, over 32 NVC fields (8 fingers, 4 fields per finger, fingers 2-5 of each hand). Other nailfold capillaries abnormalities were scored by a validated semiquantitative rating scale, in accordance with previous studies 20,21,22 .…”

Intra-and inter-observer reliability of nailfold videocapillaroscopy — A possible outcome measure for systemic sclerosis-related microangiopathy

“…Various previous studies report reliability of high magnification nailfold capillaroscopy, highlighting the implied need for standardisation [12,13,[16][17][18][19][20][21][22][23][24]. Some included only two observers [12,16,17,20,21].…”

“…Some included only two observers [12,16,17,20,21]. A small number of these studies included assessment of reliability of capillary density and/or apical width.…”

Training in Capillaroscopy: A Growing Interest: Figure 1.

“…Indeed, further strong support for the broader use of capillaroscopy arose from the recent validated description, definition, and scoring of the different scleroderma patterns using nailfold videocapillaroscopy (NVC) 11,12,13 . The presence of giant capillaries and microhemorrhages on NVC is now validated as sufficient to identify the early scleroderma pattern (early), whereas an increase in these features in addition to loss of capillaries identify the active pattern (active scleroderma pattern) and is followed by neoangiogenesis, fibrosis, and "desertification" (late scleroderma pattern; Figure 1).…”