Criteria for progressive fibrotic hypersensitivity pneumonitis in a Portuguese patient cohort.

This single-centre cohort study demonstrated that a third of f-HP patients presented with PF-ILD, as determined by progression during initial standard-of-care treatment. A usual interstitial pneumonia (UIP)/UIP-like pattern was present in >70% of patients with f-HP, and two-thirds of these patients had an FVC decline of ≥10%. PF-HP patients were also more exacerbation prone. According to recent trial data, this segment of patients can be considered possible candidates for antifibrotic treatment, with a reasonable prospect of effectiveness. Further efforts should focus on refining knowledge of longitudinal behaviour of large multicentric cohorts of f-HP patients, establishing a consensual and uniform definition of progression for use in clinical practice, as well as developing prognostic prediction tools to better (and early) inform the disease course.