Radiologic features associated to progressive fibrosing interstitial lung diseases (ILDs) other than Idiopathic Pulmonary Fibrosis (IPF)

<bold>Background:</bold> A proportion of patients with ILD other than IPF may develop a progressive fibrosing phenotype, which is associated with a poor prognosis. <bold>Aim:</bold> To explore which radiologic features on initial chest CT scan are associated with progression among non IPF-ILD patients. <bold>Methods:</bold> We consecutively enrolled patients with a diagnosis of ILD. The study population was categorized in progressors (P) and not progressors (NP) according to the latest ATS/ERS guideline. CT scans were analysed by an expert thoracic radiologist. Prevalent CT patterns [(organizing pneumonia(OP), nonspecific interstitial pneumonia (NSIP), usual interstitial pneumonia (UIP)], and ancillary features (reticulation, honeycombing (HC), ground glass opacity (GGO),bronchiectasis, mediastinal lymphadenopathy, oesophageal dilatation, consolidation) were assessed. <bold>Results:</bold> 48 ILD patients were evaluated and 15/48(31%) showed progression. P and NP were similar with regard to sex, smoking history, age at diagnosis, BMI, gastroesophageal reflux and cardiovascular diseases. At initial CT scan, UIP, NSIP, OP, reticulation, GGO and HC, mediastinal lymphadenopathy were similarly distributed among the two groups while consolidation was prevalent in the NP group (13%vs42;p=0.04). Despite the same number of central and peripheral bronchiectasis in the two groups, the number of lobes involved by bronchiectasis was higher in P (2(0-5)vs1(0-4);=p0.05). <bold>Conclusions:</bold> In non-IPF ILD, P and NP displayed similar radiological features at diagnosis with the exception of the number of lobes involved by bronchiectasis being associated with progression. Larger studies are needed to confirm these findings.