• Leticia Kawano-Dourado, Bruno G Baldi, Fernando U Kay, Olivia M Dias, Thais E H Gripp, Paula S Gomes, Ricardo Fuller, Maria T C Caleiro, Ronaldo A Kairalla, and Carlos R R Carvalho.
• Pulmonary Division, Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil.
• Clin Exp Rheumatol. 2015 Mar 1; 33 (2): 234-40.

ObjectivesInterstitial lung disease (ILD) is highly prevalent in patients with mixed connective tissue disease (MCTD). However, little is known about the long-term progression of ILD in MCTD. The aims of this study were to describe pulmonary function test (PFT) and high-resolution computed tomography (HRCT) results in long-term MCTD patients, to measure changes in PFT and HRCT results over a 10-year period, and to ascertain correlations in functional and imaging data.MethodsIn this retrospective cohort study, comparison between baseline and follow-up PFT and HRCT data was performed for 39 unselected consecutive MCTD patients.ResultsAt baseline, 51% of the patients had abnormal PFTs. Forced vital capacity (FVC) was slightly reduced at baseline (77% of predicted), but remained stable after 10 years. A relative decrease of 15% in the diffusion capacity for carbon monoxide (DLCO) was detected (from 84% to 71% of predicted, p<0.001). The median lower lobes ILD-HRCT score progressed from 7.5% at baseline to 11.2% at follow-up (p=0.02), and findings of traction bronchiolectasis and honeycombing increased (p<0.05). A moderate negative correlation was observed between functional parameters and quantification of image findings.ConclusionsFunctional and radiologic alterations suggestive of ILD in long-term MCTD patients are prevalent, mild, and progressed slightly over time. The most sensitive parameters for detecting subtle progression of ILD in MCTD patients are trends in DLCO, quantification of lower-lobes disease by HRCT (lower-lobes %ILD-HRCT score), and qualitative analysis of HRCT imaging.

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