May capillaroscopy be a candidate tool in future algorithms for SSC-ILD: Are we looking for the holy grail? A systematic review

Objective: To investigate whether nailfold videocapillaroscopy (NVC), an increasingly worldwide used non-invasive tool to reliably evaluate the peripheral microcirculation, may be an outcome measure in future screening algorithms for systemic sclerosis related interstitial lung disease (SSc-ILD). Methods: A systematic review to identify original research papers documenting an association between NVC and SSc-ILD was performed in 3 electronic databases according to the PRISMA guidelines. Subsequently, NVC parameters were subdivided according to the consented standardised capillaroscopic definitions of the EULAR Study Group on Microcirculation in Rheumatic Diseases / Scleroderma Clinical Trials Consortium on Capillaroscopy, into quantitative (capillary density, capillary dimension, capillary morphology and haemorrhages) and qualitative assessment (NVC pattern). Results: The systematic search identified 310 unique search results, of which 2 cross-sectional and 1 longitudinal study were retained. In both cross-sectional studies, the presence of SSc-ILD was found to be inversely associated with capillary density (p = .008 and p = .005). The presence of a severe (active/late) NVC pattern was evaluated and associated with the presence of SSc-ILD in one of the cross-sectional studies. In the longitudinal study, incident SSc-ILD was associated with progressive capillary loss (p = .03) and the conversion to a worse (active/late) NVC pattern (p = .001/p = .003). Conclusions: This first systematic literature review investigating the role of NVC in SSc-ILD using standardised capillaroscopic definitions uncovered associations between NVC and (incident) SSc-ILD. If large prospective studies further corroborate and elucidate these findings, NVC might possibly be a candidate outcome measure to be integrated in screening algorithms for incident/progressive SSc-ILD.