Antifibrotic Therapy Decision-Making in Pulmonary Fibrosis

Inclusion Criteria: Participants must meet all the following criteria to be eligible for inclusion in this study: 1. Pulmonary fibrosis (PF) participants in Japan. Note: This includes those clinically recognized as having idiopathic pulmonary fibrosis (IPF) or progressive pulmonary fibrosis (PPF). 2. Participants who are ≥18 years of age at the time of providing informed consent via the web-based system. 3. Participants receiving outpatient care for pulmonary fibrosis (PF) who have been introduced to this study by a referring physician. 4. Participants who have a history of taking, or are currently taking, pirfenidone, nintedanib, or nerandomilast. 5. Participants who have experienced at least one antifibrotic (AF) therapy-related adverse event (AE). * Discontinuation group only 1\) Participants who have not received AF therapy for at least 1 month prior to enrollment. 2\) Participants whose AF therapy was discontinued within 6 months prior to enrollment. 3\) Participants whose reason for discontinuing AF therapy includes at least one AF therapy-related AE. * Continuation group only 1. Participants who feel or have felt burdened by the experienced AE. 2. Participants who have continued AF therapy for a specific period (≥6 months) at the time of enrollment. Exclusion Criteria: Participants meeting any of the following criteria will be excluded from the study: <!-- --> 1. Participants currently participating in any interventional clinical trials (regardless of the study drug, excluding observational studies). 2. Participants who have undergone lung transplantation. * Discontinuation group only 1) Participants who discontinued AF therapy solely for reasons other than AE (e.g., financial reasons, disease progression).