LAUSR

Idiopathic Inflammatory Myositis (IIM) is a group of heterogeneous connective tissue diseases, primarily characterized by chronic muscle inflammation as well as myositis-specific or myositis-associated autoantibodies and a spectrum of different extra-muscular features.The most frequent organ involment in IIM is Interstitial Lung Disease (ILD), occurring in 5-80% of different IIMs cases and considered the hallmark of morbidity and mortality in patients with IIMs.To retrospectively assess the predictive factors for development of ILD in IIM patientsWe retrospectively analyzed the prevalence of ILD in a single-center cohort of 165 IIM patients. Patient data was collected from clinical charts. ILD was diagnosed by chest X-ray scan and chest CT scan. All chest CT and chest X-ray scans available and performed at our hospital were consequently re-evaluated by our expert pneumologist for uniform evaluation.Myositis-related ILD (M-ILD) was found in 52 IIM patients (31.5%): 46.15% was affected by anti-synthetase syndrome (ARS), 21.15% by polymyositis (PM), 19.23% by dermatomyositis (DM) and 13.46% by overlap myositis. The pulmonary involvement was characterized by Non-specific interstitial pneumonia (NSIP) (30.6%), Unusual Interstitial Pneumonia (UIP) (38.77%), Bronchiolitis Obliterans with Organizing Pneumonia (BOOP) (20.4%), overlap NSIP/BOOP (4.1%) and Undetermined/Unspecific pattern (6.12%). Eighty four percent of M-ILD consisted of non-smokers and 69.23% presented with dyspnea at onset.ILD was diagnosed in 90.38% of patients within the first year of IIM diagnosis (early onset ILD) and was associated with dyspnea and/or cough in 70.2% and 17% respectively. On the other hand, late onset ILD presented mostly with dyspnea and/or cough in 60% of cases and was significantly associated with anti-Ku antobodies.At onset ILD was significantly associated with: ARS (p<0.0001; OR:12.98), anti-Jo-1 (p<0.0001; OR:6.1), anti-Ro (p=0.038; OR:2.2), mechanic’s hands (p<0.0001; OR:10.41), arthritis (p=0.01; OR:2.58), polyarthritis (p=0.001; OR:4.578), dyspnea (p<0.0001; OR:9.66), and high levels of CPK (p=0.0001) and GOT (p=0.0146). By contrast, the following features: DM (p=0.012; OR:0.36), facial rash (p=0.003; OR:0.31), anti-NXP-2 (p=0.019; OR<0.0001), anti-PL-12 (p=0,03; OR<0.0001) and myositis (p<0.0001; OR:0.173) present at onset were less frequently associated with M-ILD.At multivariate analysis M-ILD was predicted by anti-Ro (p=0.0448), polyarthritis (p=0.0093) and dyspnea (p=0.0001) at onset. On the other hand, patients presenting myositis (p=0.0383) and facial rash (p=0.0398) at onset were less likely to developed M-ILD.ILD occurs in about one third of patients with IIM, mostly affected by ARS. The presence of anti-Ro antibodies as well as polyarthritis and dyspnea at onset predict the development of ILD.None declared