Nailfold capillary microscopy can suggest pulmonary disease activity in systemic sclerosis

To evaluate the association of capillaroscopic alterations with pulmonary disease activity in systemic sclerosis (SSc).

Ninety-one patients with SSc were studied by means of interview, physical examination, nailfold capillary microscopy (NCM), serology, pulmonary function tests, esophageal transit scintigraphy, Doppler echocardiography, and pulmonary high resolution computed tomography (HRCT). Pulmonary disease activity was diagnosed by the observation of ground-glass opacities on pulmonary HRCT. Capillary loss on NCM was evaluated using the avascular score: patients with mean score > or = 1 or mean number of megacapillaries per finger > or = 1 were considered to have severe capillaroscopic alterations.

Patients with higher skin scores, longer disease duration, signs of peripheral ischemia, esophageal dysfunction, antitopoisomerase I antibodies, and ground-glass opacities had higher mean avascular scores (p < or = 0.05 in all tests). The association between ground-glass opacities and higher avascular scores was particularly strong in patients with disease duration < or = 5 years. Among these patients, ground-glass opacities were present in 14 of 19 patients with severe NCM alterations, but were absent in all patients (n = 8) with mild or no NCM alterations (p < 0.001). ROC curves confirmed the ability of NCM to discriminate between patients with and without ground-glass opacities among those with disease duration < or = 5 years. However, NCM could not predict the presence of reduced pulmonary diffusing capacity.

The severity of NCM abnormalities is associated with lung disease activity in SSc, particularly when the disease duration is relatively short.