Predictive Findings of Progressive Fibrosing Interstitial Lung Disease (PF-ILD)

Background: Many fibrotic interstitial lung diseases (FILD) develop a PF-ILD. Objectives: Estimate indicative findings of progression at initial evaluation in FILD in a large retrospective cohort from Brazil. Methods: Progressive disease was characterized by any of following: death in first two years, exacerbation, prescription of oxygen not necessary during initial evaluation or a decline in FVC ≥10% of predicted values or when 2 or 3 of the following findings were found: FVC decline between 5-9%, worsening of dyspnea, and increasing extent of fibrotic changes on HRCT (INBUILD, 2019). Findings related to progression were selected by chi-square test and t-test and logistic regression. Results: 500 patients were evaluated, 56.8% females, age=62.7 ± 12,5 years. Final diagnoses were: connective tissue diseases (CTD) 32.6%, IPF 21.4%, chronic hypersensitivity pneumonitis (CHP) 20.6%, idiopathic nonspecific interstitial pneumonia (INSIP) 12.4%, unclassifiable (UILD) 6%, isolated familial ILD (F-ILD) 3.4% and others. Progressive disease was found in 231 (46.4%). By logistic multivariate analysis (excluding DCO and ExSpO2) remained associated (p<0.05) with progressive course of disease (OR; 95%CI): Velcro crackles (2.25; 1.49-3.38), CHP diagnosis (1.91; 1.13-3.24), dyspnea level (1.54;1.24-1.93) and CTD diagnosis (0.57;0.37-0.88). When Velcro were removed from the model, honeycombing became a significant predictor for progression (OR=1.62, 95%CI=1.05-2.48, p=0.028). Conclusions: Several findings are predictive of progression in FILD, including CHP diagnosis, dyspnea level, Velcro crackles or honeycombing. ILD related to CTD are associated to less progressive course of disease.