Take home messageNailfold capillaroscopy by smartphone-dermatoscope is a safe, feasible tool that may improve the identification of connective tissue disease in interstitial lung disease further to routine clinical assessment.
Methods
Study design and participantsConsecutive patients attending a specialist ILD clinic were prospectively screened for inclusion ( 18August 2016 to 24 January 2018). Eligible patients were aged 18 years, with a consensus diagnosis of CTD-ILD or IIP by ILD multidisciplinary-meeting (ILD-MDM), and able to give informed consent.CTD diagnoses were defined by international criteria for systemic sclerosis ( SSc) [3], rheumatoid arthritis (RA) [9], Sjögren's syndrome [10], mixed connective tissue disease [11], idiopathic inflammatory myositis (IIM) [12], and systemic lupus erythematosus [13]. IIPs were defined by American Thoracic Society/European Respiratory Society classification criteria [1, 14]. Of eligible participants, patients meeting IPAF criteria were separately identified [15]. CTD-ILD and IPAF classifications were confirmed by specialist Rheumatologist assessment. Patients unable to provide consent or without CTD-ILD or IIP by ILD-MDM consensus were excluded. Diagnosis at follow-up was censored on 15 June 2020. Ethical approval was granted by the Sydney Local Health District human ethics committee (protocol number X16-0111 HREC/16/RPAH/137).
DefinitionsTo delineate a well-defined CTD-ILD cohort for analysis, "CTD-ILD" included only participants fulfilling CTD classification criteria as specified. "Non-CTD ILD" included IIP and IPAF participants. Disease duration was defined as time from onset of symptoms to first clinic presentation.Considering IPAF criteria, participants with positive anti-tRNA synthetase autoantibodies, amyopathic disease, and no other features diagnostic of anti-synthetase syndrome were classified as IPAF. Anti-Ro52, anti-Mi2 and anti-SRP were considered as meeting serological IPAF criteria. "Unexplained vasculopathy" was defined as pulmonary hypertension (PH) on echocardiogram (systolic pulmonary arterial pressure [PAP] >35mmHg above right atrial pressure) [16] or right heart catheterisation (RHC;