Blood Eosinophil Counts in COPD


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Key Takeaways

  • Blood eosinophil counts (BEC) are a promising biomarker for COPD1
  • BEC may predict exacerbation risk and ICS responsiveness2,3
  • BEC should be used in conjunction with other clinical assessments to individualise COPD treatment3
  • GOLD suggest the use of blood eosinophil count thresholds to guide treatment decisions3
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Can blood eosinophil counts be used as a COPD biomarker?

Researching COPD at an inflammatory cellular level is key to guiding the future development of treatments and management strategies. Blood eosinophil counts are a promising biomarker for COPD 1, with studies showing:

  • Eosinophilic inflammation was present in 20-40% of stable COPD patients, with the amount of airway eosinophilia increasing during exacerbations 4
  • Eosinophil derived granule proteins and proinflammatory mediators promote inflammation which has been associated with increased exacerbations 5

Can blood eosinophil counts predict COPD exacerbation risk?

If your patient has stable COPD, blood eosinophil counts may help you predict their risk of exacerbations.

  • Patients with blood eosinophil counts of >340 cells/μL may have an increased risk of exacerbations, associated with a 1.76-fold increased risk of severe exacerbations.2
Results from cohort studies are not conclusive regarding the ability of blood eosinophils to predict exacerbation risk. As such, GOLD does not currently recommend that you use blood eosinophil counts to predict your patient’s exacerbations, as they don’t consider the evidence to be sufficient.3 It is therefore key to monitor your patient and modify treatment using a range of clinical assessments.

Can blood eosinophil counts predict ICS responsiveness?

Inhaled corticosteroids (ICS)/long-acting beta agonist (LABA) combination therapy is more effective than the individual components in improving lung function, health status and reducing exacerbations in patients with moderate to very severe COPD.3 However it may also increase their risk of pneumonia.6

Your patient’s blood eosinophil counts may help you identify if ICS is a suitable treatment for them.

  • GOLD recommend using blood eosinophil counts as a biomarker in conjunction with clinical assessments when deciding whether to use ICS 3
  • Blood eosinophil counts can help you to predict the likelihood of treatment benefit when using ICS 3

What do the guidelines say?

GOLD recommend assessing blood eosinophil counts within the COPD treatment algorithm.3

Consider escalating from LABA or LAMA monotherapy to ICS/LABA dual therapy if:3

  • Blood eosinophil count ≥300 cells/μL AND at least one exacerbation per year OR
  • Blood eosinophil count ≥100 cells/μL AND ≥2 moderate exacerbations or at least one severe exacerbation leading to hospitalisation
Consider escalating from LAMA/LABA dual therapy to ICS/LAMA/LABA triple therapy if:3

  • Blood eosinophil count ≥100 cells/μL in patients who develop further exacerbations on LAMA/LABA therapy
GOLD do not currently recommend using blood eosinophil counts to predict future exacerbation risk in COPD patients.3

NICE recommend considering blood eosinophil counts when determining asthmatic features or features suggesting steroid responsiveness, as part of the treatment algorithm.7 However, NICE does not specify blood eosinophil count thresholds in their treatment guidelines.

Summary

BEC are a promising biomarker for COPD when personalising treatment. 1 Treatment decisions, such as whether to add ICS to a treatment regimen to reduce exacerbations, may be supported by BEC. 3 However, given the increased risk of pneumonia associated with ICS use, blood eosinophil counts should be carefully considered alongside other clinical assessments to support individualised treatment decisions for your patients.3


References
  1. Brusselle G, Pavord ID, Landis S, Pascoe S, Lettis S, Morjaria N, Barnes N, Hilton E. Blood eosinophil levels as a biomarker in COPD. Respir Med. 2018 May;138:21-31. doi: 10.1016/j.rmed.2018.03.016
  2. Vedel-Krogh S, Nielsen SF, Lange P, Vestbo J, Nordestgaard BG. Blood eosinophils and exacerbations in chronic obstructive pulmonary disease: The copenhagen general population study. Am J Respir Crit Care Med. 2016;193(9):965-974. doi:10.1164/rccm.201509-1869OC
  3. GOLD. Gold Initiative For The Diagnosis, Management, And Prevention of Chronic Obstructive Pulmonary Disease (2019 Report). 2019.
  4. Saha S, Brightling CE. Eosinophilic airway inflammation in COPD. Int J Chron Obstruct Pulmon Dis. 2006;1(1):39-47. doi:10.2147/copd.2006.1.1.39
  5. George L, Brightling CE. Eosinophilic airway inflammation: Role in asthma and chronic obstructive pulmonary disease. Ther Adv Chronic Dis. 2016;7(1):34-51. doi:10.1177/2040622315609251
  6. Yang IA, Clarke MS, Sim EH, Fong KM. Inhaled corticosteroids for stable chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2012;(7):CD002991. doi:10.1002/14651858.cd002991.pub3
  7. NICE. Chronic obstructive pulmonary disease in over 16s: diagnosis and management. 2018.

PM-GB-CPU-WCNT-190003 - April 2019

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PM-GB-CAU-WCNT-190006
March 2019