Clinical meaning of IPAF in a real-life cohort of IPF patients

Background: IPAF (interstitial lung disease with autoimmune features) is a research category recently introduced with limited data on prognosis and natural history. The aim of this study was to evaluate the characteristics of patients meeting IPAF criteria in a cohort of patients previously diagnosed with IPF. Methods: We retrospectively analyzed the medical records of IPF diagnoses at or center from 2002 until 2016. We reassigned IPF diagnoses according to the 2018 ATS/ERS guidelines and IPAF diagnoses according to ERS statement. We extracted data regarding demographics, medications, smoking history, laboratory results (autoimmunity) and pulmonary function. Results: Among 360 IPF-diagnoses, we identified: Group A composed of 289 IPF-only patients; Group B composed of 49 IPF patients with positive auto-antibodies (including anti-thyroid); Group C (IPF/IPAF) composed of 22 patients meeting IPAF criteria. IPF/IPAF patients were more frequently female (40%) (compared respectively to 17%females in group A and 30% in group B, p= 0.005). Conclusions: Reflux and arthralgia were the most frequent clinical manifestations in the IPAF group (respectively 23% and 55%), whereas in IPF-only group reflux was described in 26%(p 0.0065) and arthralgia in 2% of cases (p