Background Mixed Connective Tissue Disease (MCTD) is characterized by high levels of autoantibodies against U1 small nuclear ribonucleoprotein (RNP) and clinical manifestations also found in Systemic Sclerosis, Systemic Lupus Erythematosus, Rheumatoid Arthritis and Polymyositis. Interstitial Lung Disease (ILD) is a severe complication in MCTD and has been reported to affect between 35% and 85% (1) in different cohorts.
Objectives Here we present a predicting model of ILD in an unselected nationwide MCTD cohort aiming to assist clinicians in identifying MCTD patients with ILD.
Methods 135 patients with high resolution computed tomography (CT) available for systematic evaluation were included from our nationwide MCTD cohort. Abnormal CT findings of ground glass attenuation and reticular patterns were defined as ILD. Pulmonary function tests were performed within 2 months of the HRCT examination. Serum levels of anti-RNP and Ro-52 autoantibody were determined by line immunoassay (ANA Profile 5 Euroline Blot test kit, Euroimmun, Lübeck, Germany). Logistic regression analyses were used to find the predictive factors of ILD. Variables at a significant level of P<0.25 where considered a candidate in the prediction model by manual backward elimination procedure in addition to age and gender.
Results Results: 52 patients (38%) had evidence of ILD on HRCT. The predictive model is shown in Table 1. P=0.55 for goodness of fit test and P=0.80 for area under ROC curve.
Conclusions Risk factors of ILD in MCTD are DLCO less than 60% of predicted, high titer RNP antibodies, no previous arthritis and increasing age.
Gunnarsson R, Hetlevik SO, Lilleby V, Molberg O. Mixed connective tissue disease. Best Pract Res Clin Rheumatol. 2016;30(1):95–111.
Disclosure of Interest None declared