What is IPF?
Idiopathic pulmonary fibrosis (IPF), the most common form of lung fibrosis, is a progressive, irreversible and life-limiting condition.1,2,3 IPF is one of more than 200 lung diseases known as interstitial lung diseases (ILDs), relating to the interstitium – the tissue between the air sacs of the lungs.4 Patients with IPF present with increasing breathlessness and fatigue and many also develop a persistent, dry cough, which can prove difficult to treat.3,5
IPF occurs when tissue in the lungs becomes inflamed and scarred (lung fibrosis). Fibrosis, or scarring, can be part of the healing response to injury, but fibrosis as a disease process occurs when restoration to normal tissue does not occur.6 The scar tissue, which forms on the alveoli, causes the lungs to become stiff and less elastic, which impairs gas exchange.3,7,8 This impairment of gas exchange leads to a decline in lung function and, ultimately, death from respiratory failure.3
Over time, the lungs develop a ‘honeycomb appearance’. Although its identification is often subjective, honeycombing is a common feature of IPF seen on high-resolution computed tomography (HRCT) and is crucial for an accurate diagnosis.9
The honeycomb changes (arrowheads) and traction bronchiectasis (arrow) indicate the presence of advanced fibrosis.
What causes IPF?
‘Idiopathic’ means the cause of the scarring to the lungs in IPF is unknown.11 However, potential links with some environmental factors have been identified.12 Genetics could also play a role in IPF.13
While cigarette smoking is one of the most recognised risk factors for development of IPF, other risk factors may include exposure to metal dust, wood dust, asbestos, silica or coal.12,14 Occupations related to farming and livestock have also been associated with an increased risk of developing IPF.12
Some research suggests that the scarring to the lungs may be related to acid reflux from the stomach.15 There is also some evidence that connects viral and bacterial infections with IPF and other fibrotic lung diseases.16
ILDs can also be caused by chemotherapeutic agents, antibiotics, antiarrhythmic drugs, and immunosuppressive agents.17
Although it should be recognised that where the exposure to occupational triggers, or specific medications, is linked with ILD, the cause is known and therefore the condition is no longer ‘idiopathic’.
How common is IPF?
While IPF is still relatively rare, there is evidence to suggest it is more common than previously thought.18 According to the European Medicines Agency definition, a rare disease affects ≤5 in 10,000 people.19
The National Institute for Health and Care Excellence (NICE) estimates that 15-25 people per 100,000 in the UK have IPF.20 However, evidence exists to suggest it may be closer to more than double this estimate. According to an analysis of the British Thoracic Society’s 2006 ‘Burden of Lung Disease’ report, an estimated 32,500 people in the UK live with IPF, a prevalence rate of about 50 people every 100,000. There are around 6,000 new cases diagnosed each year.18
Who does IPF affect?
Most commonly, people diagnosed with IPF are over the age of 40.21 The chances of diagnosis increase significantly as people get older, with around 85% of diagnoses being made in people aged over 70. IPF is 50% more common in men than women.18
Unlike other lung diseases, rates of IPF in the UK do not appear to be affected by socio-economic status. However, there are regional differences in prevalence. According to data collected by the British Lung Foundation, prevalence is generally highest in Northern Ireland, north-west England, Scotland and Wales, and IPF is least common in London. The reasons for this are unknown.22
What are the survival rates?
5,300 people every year die from IPF.18 The median survival rate of patients with IPF is 3 years following diagnosis, with 34% of patients surviving 5 years.23 This 5-year survival rate is worse than some common cancers, including bowel or colorectal (58-59%), breast (85%) and prostate cancer (87%).23,24,25
Seasonal variability has been observed in IPF death rates, although the precise aetiology associated with this is not well understood. Findings from research using death records in the USA found that the mortality rate among patients with IPF or pulmonary fibrosis (PF) was 17.1% higher in winter (p < 0.0001), 12.7% higher in spring (p < 0.0001), and 5.2% higher in autumn (p = 0.0002) than in summer months.26
1Barrón GM et al. Characterizing the Role of Novel Protein, P311, in Pulmonary Repair Mechanisms. American Thoracic Society Conference 2018. A21. Poster discussion, May 20, San Diego, California
2Costabel U. The changing treatment landscape in idiopathic pulmonary fibrosis. Eur Respir Rev 2015;24(135):65-68
3Senanayake S et al. Patients’ experiences of coping with Idiopathic Pulmonary Fibrosis and their recommendations for its clinical management. PLoS ONE 2018;13(5): e0197660
4National Heart, Lung and Blood Institute. Interstitial Lung Diseases. Available at: https://www.nhlbi.nih.gov/health-topics/interstitial-lung-diseases. Last accessed November 2019
5National Institute for Health and Care Excellence (NICE). Idiopathic pulmonary fibrosis in adults: diagnosis and management. CG163. Available at: https://www.nice.org.uk/guidance/cg163/resources/idiopathic-pulmonary-fibrosis-in-adults-diagnosis-and-management-pdf-35109690087877. Last accessed November 2019
6Thoracic. Chapter 10 – Interstitial Lung Disease. Available at: https://www.thoracic.org/patients/patient-resources/breathing-in-america/resources/chapter-10-interstitial-lung-disease.pdf. Last accessed November 2019
7Travis WD et al. An official American Thoracic Society statement: update of the international multidisciplinary classification of the idiopathic interstitial pneumonias. Am J Respir Crit Care Med 2013;188: 733–748
8Thannickal VJ et al. Matrix Biology of Idiopathic Pulmonary Fibrosis A Workshop. The American Journal of Pathology 2014;184(6):1643-1651
9Devaraj A. Imaging: how to recognise idiopathic pulmonary fibrosis. European Respiratory Review 2014;23: 215-219; doi: 10.1183/09059180.00001514
10Meltzer EB et al. Idiopathic Pulmonary Fibrosis. Fishman's Pulmonary Diseases and Disorders 2007; 4th edition PW: Chapter 70
11NHS. Idiopathic pulmonary fibrosis: Overview. Available at: www.nhs.uk/conditions/idiopathic-pulmonary-fibrosis. Last accessed November 2019
12Swigris JJ. Idiopathic pulmonary fibrosis: diagnosis and epidemiology. Clinics in Chest Medicine 2012;33(1): 41–50. doi:10.1016/j.ccm.2011.12.001
13Sgalla et al. Idiopathic pulmonary fibrosis: pathogenesis and management. Respiratory Research 2018 22;19(1):32
14Oh CK, Murray LA, and Molfino NA. Smoking and Idiopathic Pulmonary Fibrosis. Pulmonary Medicine 2012:808260
15Bédard MeD, et al. Meta-analysis of Gastroesophageal Reflux Disease and Idiopathic Pulmonary Fibrosis. Chest 2019 155(1):33-43
16Moore BB. Viruses in Idiopathic Pulmonary Fibrosis. Etiology and Exacerbation. Ann Am Thorac Soc 2015. Nov 12 Suppl 2: S186-92
17Schwaiblmair M, et al. Drug induced interstitial lung disease. Open RespirMed J 2012;6:63–74
18Snell N, Strachan D, Hubbard R, et al. P272 Epidemiology of idiopathic pulmonary fibrosis in the UK: findings from the British Lung Foundation’s ‘Respiratory health of the nation’ project. Thorax 2016;71:A236
19European Medicines Agency. Committee for Orphan Medicinal Products (COMP). Available at: https://www.ema.europa.eu/en/committees/committee-orphan-medicinal-products-comp. Last accessed November 2019
20National Institute for Health and Care Excellence (NICE). Idiopathic pulmonary fibrosis in adults. QS79. Available at: https://www.nice.org.uk/guidance/qs79/resources/idiopathic-pulmonary-fibrosis-in-adults-pdf-2098856506309. Last accessed November 2019
21British Lung Foundation. Idiopathic pulmonary fibrosis statistics. Available at: https://statistics.blf.org.uk/pulmonary-fibrosis. Last accessed November 2019
22British Lung Foundation. The battle for breath - the impact of lung disease in the UK. 2016. Available at: https://www.blf.org.uk/policy/the-battle-for-breath-2016. Last accessed November 2019
23Strongman H, Kausar I, Maher TM. Incidence, Prevalence, and Survival of Patients with Idiopathic Pulmonary Fibrosis in the UK. Adv Ther 2018;35:724–736
24Office for National Statistics. Cancer survival in England: adult, stage at diagnosis and childhood - patients followed up to 2018. Available at: www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/cancersurvivalinengland/stageatdiagnosisandchildhoodpatientsfollowedupto2018. Last accessed November 2019
25Cancer Research UK. Cancer incidence for common cancers. Available at: www.cancerresearchuk.org/health-professional/cancer-statistics/incidence/common-cancers-compared#heading-Zero. Last accessed November 2019
26Olson AL et al. Seasonal variation: mortality from pulmonary fibrosis is greatest in the winter.
Chest 2009; 136(1):16-22