Clinical utilization of airway inflammatory biomarkers in the prediction and monitoring of clinical outcomes in patients with chronic obstructive pulmonary disease

ABSTRACT

Introduction

Chronic obstructive pulmonary disease (COPD) accounts for 545 million people living with chronic respiratory disorders and is the third leading cause of morbidity and mortality around the world. COPD is a progressive disease, characterized by episodes of acute worsening of symptoms such as cough, dyspnea, and sputum production.

Areas covered

Airway inflammation is a prominent feature of COPD. Chronic airway inflammation results in airway structural remodeling and emphysema. Persistent airway inflammation is a treatable trait of COPD and plays a significant role in disease development and progression. In this review, the authors summarize the current and emerging biomarkers that reveal the heterogeneity of airway inflammation subtypes, clinical outcomes, and therapeutic response in COPD.

Expert opinion

Airway inflammation can be broadly categorized as eosinophilic (type 2 inflammation) and non-eosinophilic (non-type 2 inflammation) in COPD. Currently, blood eosinophil counts are incorporated in clinical practice guidelines to identify COPD patients who are at a higher risk of exacerbations and lung function decline, and who are likely to respond to inhaled corticosteroids. As new therapeutics are being developed for the chronic management of COPD, it is essential to identify biomarkers that will predict treatment response.

KEYWORDS:

• Airway inflammation
• COPD
• Exacerbations
• Biomarkers

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Declaration of interest

DD Sin has received honorarium from GSK for a speaking engagement on COPD and has received research funding from Nextone. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer Disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Article Highlights

1. Clinical management of COPD is challenged by heterogeneity in disease presentation; therefore, identifying biomarkers may offer an opportunity to improve our understanding of the disease endotypes and enable precision medicine.

2. Persistent airway inflammation contributes to disease severity and exacerbations.

3. Six-minute walk distance and its change over time are predictive of mortality in patients with severe COPD.

4. The correlation in eosinophil levels between sputum and peripheral blood (BEC) is inconsistent across the studies.

5. Type 2 or eosinophilic airway inflammation plays an important role in the severity and progression of COPD and is associated with respiratory exacerbations.

6. Combining BEC and fractional exhaled nitric oxide (FeNO) biomarkers may improve the detection of both moderate and severe COPD exacerbations.

7. FeNO may be a reliable predictor to gauge therapeutic responses to inhaled corticosteroids, however, further investigations should be done to confirm this.

Additional information

Funding

This paper was not funded.