Background Nailfold videocapillaroscopy (NVC) is an imaging technique representing a reliable tool for the classification, diagnosis and monitoring of systemic sclerosis (SSc) patients. The capillaroscopic skin ulcer index (CSURI) was suggested to identify patients at risk of developing digital ulcers (DU) .
Objectives This study aims (1) to describe the practicality of the CSURI in clinical practice, (2) to describe the change of CSURI during follow-up, and (3) to assess associations between the change in CSURI and demographic and disease characteristics.
Methods This Swiss multicentre, prospective, observational study analysed SSc patients with a history of active DU. Demographic characteristics and routine clinical data were recorded and patients underwent NVC at baseline and at the follow-up visit.
The centres' investigators were trained to perform NVC and, the nailfolds of 8 fingers (digit 2–5 on both hands) were examined if possible. All images were stored centrally and separately analysed by two extensively trained and experienced reviewers (OD & UAW) separately.
In each NVC image the total number of capillaries in the distal row, the number of megacapillaries and the maximum diameter of the megacapillaries were assessed. Based on these 3 characteristics, the CSURI was calculated according to Sebastiani et al.  for patients with at least 1 megacapillary present. Data were analysed descriptively.
Results Between 2011 and 2015, 61 patients fulfilled the eligibility criteria and had at least one follow-up visit (median observation time 1.0 years, interquartile range [IQR] 1.0–1.1). Of these patients, more than a third (reviewer 1: n=24 patients, 39%; reviewer 2: n=26 patients, 43%) had no megacapillaries present on NVC on any assessed finger and hence the CSURI could not be calculated for those either at baseline or follow-up. Therefore, this analysis is based on the remaining 34 patients who had at least one megacapillary present on NVC at baseline and at follow-up by both reviewers (26% male; median age 57 years, IQR 48–65 years).
The median baseline CSURI scores according to reviewer 1 was 5.3 (IQR 2.6–16.3) increasing to a median of 5.9 (1.3–12.0) at follow-up. The CSURI as evaluated by reviewer 2 reduced from baseline (median 6.4, IQR 2.4–12.5) to follow-up (5.0, IQR 1.7–10.0).
None of the assessed demographic or disease characteristics (Box 1) were associated with the changes in the CSURI between baseline and follow-up for the scores obtained by reviewer 1 and reviewer 2 at the same time; although the limited sample size should be kept in mind interpreting this lack of association.
Conclusions In this study, around 40% of patients could not be evaluated with the CSURI due to the absence of megacapillaries on NVC. Clinical decisions based on the CSURI in routine practice should be made with caution, as it can vary greatly between assessors even if they are extensively trained.
Sebastiani M, et al. Predictive role of capillaroscopic skin ulcer risk index in systemic sclerosis: a multicentre validation study. ARD 2012;71:67–70.
Acknowledgements This study was supported by Actelion Pharma Schweiz AG.
Disclosure of Interest U. Walker: None declared, V. Jaeger: None declared, L. Arlettaz: None declared, M. Banyai: None declared, J. Beron Employee of: Actelion Pharma Schweiz AG, C. Chizzolini: None declared, E. Gröchenig: None declared, R. Mueller: None declared, F. Spertini: None declared, P. Villiger: None declared, O. Distler Grant/research support from: 4 D Science, AbbVie, Actelion, Active Biotec, Bayer, BiogenIdec, BMS, Boehringer Ingelheim, ChemomAb, EpiPharm, espeRare foundation, Genentech/Roche, GSK, Inventiva, iQone Healthcare, Lilly, medac, Mepha, MedImmune, Mitsubishi Tanabe Pharma, Pharmacyclics, Pfizer, Sanofi, Serodapharm and Sinoxa, Consultant for: 4 D Science, AbbVie, Actelion, Active Biotec, Bayer, BiogenIdec, BMS, Boehringer Ingelheim, ChemomAb, EpiPharm, espeRare foundation, Genentech/Roche, GSK, Inventiva, iQone Healthcare, Lilly, medac, Mepha, MedImmune, Mitsubishi Tanabe Pharma, Pharmacyclics, Pfizer, Sanofi, Serodapharm and Sinoxa