Abstract Rationale Antifibrotic therapies slow disease progression in patients with progressive fibrosing interstitial lung diseases (ILD). However, long-term adherence in clinical practice is difficult to maintain mainly due to side effects. Real-world data on adherence and its association with prognosis are still limited. Methods Health claims data of patients having started antifibrotic therapy with nintedanib or pirfenidone between 2019 and 2024 collected by the Austrian Health Insurance Fund (ÖGK) covering 7.6 million persons or 82% of the Austrian population were retrieved. Patients who died within four months of treatment initiation were excluded, adherence was defined as pickup of ≥ 10 monthly dose packages of either medication. Overall (OS) and event-free survival (EFS; defined as time to hospitalization or death) and their determinants were examined using Kaplan-Meier analyses, log-rank tests and multivariate Cox regression. Results Of 1,797 patients identified (mean age 71.1 years, 66% male), 90.8% were prescribed Nintedanib, and 9.2% Pirfenidone. 1,567 patients were available for the adherence analysis. Adherent patients (n = 949, 60.6%) had significantly longer median OS than non-adherent patients (66 vs. 47 months; p 0.001). Also, EFS was prolonged (33 vs. 16 months; p 0.001). In multivariate analysis for mortality, adherence was an independent protective variable (HR 0.42; 95% CI 0.34-0.50), while age ≥70 years, male sex, pre-existing long-term oxygen therapy and prior hospitalizations were associated with increased mortality. There was no difference in survival between nintedanib and pirfenidone-treated patients (p = 0.909). Of 1,671 patients having received Nintedanib, 814 (48.7%) received only the 150mg dose (32.2% died), 505 (30.2%) had a dose reduction from 150 to 100mg (28.7% died), 241 (14%) only received 100mg (42.3% died), and 111 (6.6%) had a dose increase from 100 to 150mg (30.6% died). Conclusion In this large, nationwide real-world cohort, adherence to antifibrotic therapy was a strong predictor of survival. Supporting adherence by individualized dose management schedules should be pivotal elements in ILD patient care. This abstract is funded by: None
Lang et al. (2026) studied this question.