Disease trajectories in interstitial lung diseases – Data from the EXCITING-ILD Registry

<bold>Background:</bold> ILD comprise a heterogeneous group of mainly chronic lung diseases with different disease trajectories with PF-ILD in up to 50% of patients. <bold>Methods:</bold> Course of disease was classified as significant (absolute VC decline >10 %) or moderate progression (VC decline 5 % to 10 %), stable disease (VC decline or increase <5 %) or improvement (VC increase ≥5 %). A second definition for PF-ILD included absolute decline in VC % predicted ≥10 % within 24 months or ≥ 1 respiratory-related hospitalisation. Risk factors were determined by Cox proportional-hazard models and by logistic regression, for survival time and time to progression by Kaplan-Meier curves. <bold>Results:</bold> From 601 included patients, progression was detected in 50.6 % (n= 304) with shortest median time to progression in iNSIP (median 14.6 months) and IPF (median 18.9 months). Reasons for the determination as PF-ILD were mainly deterioration in PFT (57.8%) and respiratory hospitalisations (40.6%). In multivariate analyses reduced baseline VC together with age were significant predictors for progression (OR= 1.00, p< 0.001). Higher GAP indices were a significant risk factor for a shorter survival time (GAP stage III vs. I HR= 9.06, p< 0.001). A significant shorter survival time was found in IPF compared to sarcoidosis (HR= 0.04, p< 0.001), CTD-ILD (HR= 0.33, p< 0.001), and HP (HR= 0.30, p< 0.001). Patients with at least one reported ILD exacerbation (AE) as a reason for hospitalisation had a significant shorter median survival time (7.3 years, HR= 0.39, p< 0.001). <bold>Conclusion:</bold> Disease progression is common in ILD. Most important risk factors are impaired baseline VC and higher age, as well as AE and respiratory hospitalisations.