Critical threat of ILDs

Pulmonary fibrosis is a critical threat across a broad range of ILDs1–4

ILD patients with the HRCT scans in their hands.

Pulmonary fibrosis is characterized by the often chronic and irreversible scarring of lung tissue,2,3 and can become a key driver of irreversible lung damage and early mortality that warrants urgent identification and intervention1–4

Acute exacerbation of ILD can be a particularly deadly threat that could strike at any time in some patients with pulmonary fibrosis5–8


There are a wide range of ILDs that are characterized by pulmonary fibrosis, such as IPF, iNSIP, unclassifiable ILD, cHP, as well as CTD-ILDs.1–4,14 ILD occurs in ~15% of CTD patients and at higher rates in certain conditions, such as SSc and RA.10

ILDs make up a diverse group of more than 200 heterogeneous lung disorders, mostly classified as rare or only infrequently seen in clinical practice1,10,11

Although individual fibrotic ILDs can be rare compared to other conditions, collectively they affect a considerable number of patients, representing a substantial burden of disease14


The progressive fibrosing phenotype is characterized by increased extent of fibrosis, worsening respiratory symptoms and lung function decline1,10,12,13

Relative prevalence of ILDs, and proportion estimates of patients who develop a progressive fibrosing phenotype, accompanied by detailed equivalent information on CTD-ILDs14

Prevalence of progressive fibrosing phenotype in ILDs / CTD-ILDs

Adapted from: Wijsenbeek M, Cottin V. N Engl J Med. 2020;383:958–968.

Learn more about the progressive fibrosing phenotype


See what Vincent Cottin, Professor of Respiratory Medicine, has to say about the importance of pulmonary fibrosis in IPF and in a range of non-IPF ILDs


Fibrosis is an excessive deposition of extracellular matrix within the lungs. Pulmonary fibrosis is actually characterised histologically, and pulmonary fibrosis occurs in a number of conditions, including idiopathic pulmonary fibrosis, which is most typical of these conditions characterised by progressive onset, but what we have learned in recent years is the importance also of pulmonary fibrosis in other conditions. What we call pulmonary fibrosis may also occur in other conditions, for example, in connective tissue disease, scleroderma, rheumatoid arthritis with interstitial lung disease, and other connective tissue disease. In chronic HP, chronic hypersensitivity pneumonitis, which is related to exposure to an antigen, there are acute forms that are reversible, but there are also chronic forms that often include some fibrosis.

What could the threat posed by fibrotic ILDs mean for your patients?

  1. Flaherty KR, Brown KK, Wells AU, et al. Design of the PF-ILD trial: a double-blind, randomised, placebo-controlled phase III trial of ... in patients with progressive fibrosing interstitial lung disease. BMJ Open Resp Res. 2017;4(1):e000212.

  2. Patterson KC, Strek ME. Pulmonary fibrosis in sarcoidosis. Clinical features and outcomes. Ann Am Thorac Soc. 2013;10(4):362-370. 

  3. Caban JJ, Yao J, Bagci U, Mollura DJ. Monitoring pulmonary fibrosis by fusing clinical, physiological, and computed tomography features. Conf Proc IEEE Eng Med Biol Soc. 2011;6216-6219.
  4. Wells AU, Brown KK, Flaherty KR, Kolb M, Thannickal VJ, on behalf of the IPF Consensus Working Group. Eur Resp J. 2018;51:1800692.
  5. Kolb M, Bondue B, Pesci A, et al. Acute exacerbations of progressive-fibrosing interstitial lung diseases. Eur Respir Rev. 2018;27(150):pii:180071.
  6. Collard HR, Ryerson CJ, Corte TJ, et al. Acute exacerbation of idiopathic pulmonary fibrosis: an international working group report. Am J Respir Crit Care Med. 2016;194(3):265–275.
  7. Song JW, Hong S-B, Lim C-M, et al. Acute exacerbation of idiopathic pulmonary fibrosis: incidence, risk factors and outcome. Eur Respir J. 2011;37(2):356–363.
  8. Song JW, Lee HK, Lee CK, et al. Clinical course and outcome of rheumatoid arthritis-related usual interstitial pneumonia. Sarcoidosis Vasc Diffuse Lung Dis. 2013;30(2):103-112.
  9. Wijsenbeek M, Cottin V. Spectrum of Fibrotic Lung Diseases. N Engl J Med. 2020;383:958–968.
  10. Cottin V, Hirani N, Hotchkin D, et al. Presentation, diagnosis and clinical course of the spectrum of progressive-fibrosing interstitial lung diseases. Eur Respir Rev. 2018;27(150):180076. 
  11. Demedts M, Wells AU, AntÓ JM, et al. Interstitial lung diseases: an epidemiological overview. Eur Respir J Suppl. 2001;18(suppl32):2s-16s.
  12. Cottin V, Wollin L, Fischer A, et al. Fibrosing interstitial lung diseases: knowns and unknowns. Eur Respir Rev. 2019b;28(151):pii:180100.
  13. Kolb M, Vašáková M. The natural history of progressive fibrosing interstitial lung diseases. Respir Res. 2019;20(1).
  14. Wijsenbeek M, Cottin V. Spectrum of Fibrotic Lung Diseases. N Engl J Med. 2020;383:958–968. Supplementary Appendix.
  15. Fischer A and Distler J. Progressive fibrosing interstitial lung disease associated with systemic autoimmune diseases. Clin Rheumatol. 2019;38(10):2673–2681. 
  16. Mathai SC and Danoff SK. Management of interstitial lung disease associated with connective tissue disease. BMJ. 2016;352:h6819.
  17. Wallace B, Vummidi D, Khanna D. Management of connective tissue diseases associated interstitial lung disease: a review of the published literature. Curr Opin Rheumatol. 2016;28(3):236–245.
  18. Spagnolo P, Cordier JF, Cottin V. Connective tissue diseases, multimorbidity and the ageing lung. Eur Respir J. 2016;47(5):1535–1558.
  19. Tomiyama F, Watanabe R, Ishii T, et al. High Prevalence of Acute Exacerbation of Interstitial Lung Disease in Japanese Patients with Systemic Sclerosis. Tohoku J Exp Med. 2016;239, 297–305.
  20. Okamoto M, Fujimoto K, Sadohara J, et al. A retrospective cohort study of outcome in systemic sclerosis-associated interstitial lung disease. Respiratory Investigation. 2016;54, 445–453. 

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