Assessing the role for nailfold videocapillaroscopy in interstitial lung disease classfication: a systematic review and meta-analysis

Objectives The nailfold videocapillaroscopy (NVC) has been known to assist with interstitial lung disease (ILD) classification. However, evidence on its diagnostic efficacy is limited, particularly in some connective tissue disease-related interstitial lung diseases (CTD-ILD), and in interstitial pneumonia with autoimmune features (IPAF). This study aimed to address this limitation by conducting a meta-analysis on the efficacy of the NVC in ILD subgroups of CTD-ILD, IPAF and idiopathic pulmonary fibrosis (IPF). Methods MEDLINE, EMBASE, CENTRAL were screened from inception to December 2020 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies that report prevalence of nailfold abnormalities (NVC+) in CTD-ILD, IPAF and IPF cohorts were included. Data were presented as prevalence ratio (PR) with 95% CI using a random-effects model. Quality of evidence was assessed using GRADE criteria. Results Twenty-one studies were eligible. Prevalence of NVC+ was highest in CTD-ILD; PR (95 CI%) 80.4% (74.3%, 85.3%), followed by IPAF; 27.4% (10.9%, 53.7%), and IPF; 13.8% (5.7%, 29.9%). Late scleroderma pattern was the most prevalent nailfold pattern; 40.4% (28.1%, 54.1%) in our CTD-ILD cohort. Quality of evidence was low for CTD-ILD, IPAF and IPF cohorts, moderate for the late scleroderma pattern cohort. Conclusion NVC can increase the diagnostic accuracy of ILD when used in a multi-disciplinary setting, and appears to have greatest utility in CTD-ILD, followed by IPAF and IPF. The Late Scleroderma Pattern was the most frequent nailfold capillary pattern in SSc-ILD. Future research will allow for greater understanding of the prognostic value of the NVC in ILD.