{ "abstract": "Background\n\nProgressive pulmonary fibrosis (PPF) represents a common disease behaviour across fibrotic interstitial lung diseases (F-ILDs). PPF was defined in 2022, but data on extent and prognosis remain limited. The aim of this study was to determine the proportion of those with F-ILD who progress to PPF, investigate predictors of PPF and compare survival between PPF and non-PPF patients.Methods\n\nThis prospective longitudinal cohort study included all incident cases of F-ILD diagnosed at Danish tertiary interstitial lung disease (ILD) centres between 1 June 2016 and 31 May 2017. Patients with idiopathic pulmonary fibrosis or fewer than two pulmonary function tests were excluded. Data were obtained from the Danish ILD database (DANILDA) and national registries. PPF was defined according to the 2022 criteria. Survival was analysed using Kaplan-Meier estimates and Cox regression with PPF modelled as a time-dependent covariate and delayed entry handled by left truncation.Results\n\nOf the 197 patients included, 57% developed PPF during 4 years of follow-up (median 13 months). No baseline variables predicted PPF development. The PPF group experienced a greater annual decline in forced vital capacity (FVC) (adjusted mean difference -140 mL·year⁻¹; p=0.001) and diffusing capacity of the lung for carbon monoxide (-2.97 percentage points per year; p=0.009) than the non-PPF group. The 3-, 5- and 7-year survival rates were 73%, 58% and 48%, respectively, among those with PPF, and did not differ significantly between people with PPF and those with non-PPF. A higher baseline ILD-gender-age-physiology index (ILD-GAP) stage was independently associated with decreased survival (hazard ratio 2.64; p<0.001).Conclusion\n\nIn this nationwide real-world cohort, almost six out of 10 patients with F-ILD developed PPF within 4 years. Although patients with PPF exhibited a greater annual decline in FVC, survival rates did not differ between people with PPF and those with non-PPF.", "abstract_shown": true, "affiliations": [ "Department of Medicine, Lillebaelt Hospital, Vejle, Denmark.", "Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.", "Medical Department, Gødstrup Hospital, Herning, Denmark.", "Department of Respiratory Diseases and Allergy, Aarhus University Hospital, Aarhus, Denmark.", "Department of Respiratory Diseases, Aalborg University Hospital, Aalborg, Denmark.", "Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.", "South Danish Centre for Interstitial Lung Diseases (SCILS), Department of Respiratory Medicine, Odense University Hospital, Odense, Denmark.", "Odense Respiratory Research Unit (ODIN), Department of Clinical Research, University of Southern Denmark, Odense, Denmark.", "Department of Respiratory Medicine, University of Copenhagen, Herlev-Gentofte Hospital, Hellerup, Denmark.", "Department of Clinical Medicine, Aarhus University, Aarhus, Denmark." ], "article_type": "research article", "arxiv": null, "author_total": 9, "authors": [ { "affs": [ 0, 1 ], "name": "Line Kølner-Augustson", "orcid": "0000-0002-3022-7105" }, { "affs": [ 2 ], "name": "Malene Knarborg", "orcid": "0000-0003-2398-9096" }, { "affs": [ 3 ], "name": "Nanna Makholm", "orcid": "0000-0002-9794-0829" }, { "affs": [ 4, 5 ], "name": "Thomas Prior", "orcid": "0000-0002-0668-8454" }, { "affs": [ 6, 7 ], "name": "Jesper Rømhild Davidsen", "orcid": "0000-0003-4128-4014" }, { "affs": [ 8 ], "name": "Saher Burhan Shaker" }, { "affs": [ 3, 9 ], "name": "Elisabeth Bendstrup", "orcid": "0000-0002-4238-6963" }, { "affs": [ 0, 1 ], "name": "Anders Løkke", "orcid": "0000-0002-6905-4141" }, { "affs": [ 0, 1 ], "name": "Ole Hilberg", "orcid": "0000-0002-3075-3463" } ], "bibtex": "https://research.draconitic.com/paper/fgg9tj05g5j8h.bib", "cited_by": 0, "doi": "10.1183/23120541.00476-2026", "fulltext_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13725832/?tool=EBI", "id": "fgg9tj05g5j8h", "issns": [ "2312-0541" ], "landing_url": "https://europepmc.org/article/PMC/PMC13725832", "language": "eng", "licence": "CC-BY-NC", "licence_label": "CC BY-NC", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/", "metadata_licence": null, "native_subjects": [ [ "heading", "13" ], [ "heading", "Interstitial Lung Diseases" ], [ "heading", "Original Research Article" ], [ "openalex", "2740|Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis" ] ], "openalex": "W7167801600", "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13725832/pdf/?tool=EBI", "pmcid": "PMC13725832", "pmid": "42974034", "published": "2026-11-01", "publisher": "European Respiratory Society", "ris": "https://research.draconitic.com/paper/fgg9tj05g5j8h.ris", "sources": [ { "first_seen": "2026-11-03T15:20:51Z", "native_id": "PMC:PMC13725832", "source": "europepmc", "url": "https://europepmc.org/article/PMC/PMC13725832" }, { "first_seen": "2026-11-04T15:20:47Z", "native_id": "MED:42974034", "source": "europepmc", "url": "https://europepmc.org/article/MED/42974034" }, { "first_seen": "2026-11-05T12:22:17Z", "native_id": "PMC13725832", "source": "pmc", "url": "https://doi.org/10.1183/23120541.00476-2026" } ], "subjects": [ { "field": "medicine", "origin": "openalex:2740|Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis", "subfield": "general" } ], "title": "Progressive pulmonary fibrosis in fibrotic interstitial lung disease: a Danish cohort study", "title_text": "Progressive pulmonary fibrosis in fibrotic interstitial lung disease: a Danish cohort study", "type": "peer-reviewed", "updated_at": "2026-11-06T12:21:55Z", "url": "https://research.draconitic.com/paper/fgg9tj05g5j8h", "venue": "ERJ open research", "versions": [] }