HMN 2025: How Blood tests and sputum analysis help predict COPD exacerbation risks

Identifying exacerbation risks of COPD
Time to subsequent AECOPD among patients with absolute eosinophil difference?Lung (2025). DOI: 10.1007/s00408-025-00792-9

A research team from the LKS Faculty of Medicine at the University of Hong Kong (HKUMed) has highlighted recent advances in understanding and managing COPD, particularly in relation to its exacerbations. The key findings indicate that patients’ risk profiles can be assessed by measuring blood eosinophil counts at various time points and the isolation of Pseudomonas aeruginosa in sputum, which can facilitate personalized treatment. The study is published in the journal Lung.

COPD is one of the most common chronic diseases both locally and worldwide, placing a significant burden on patients and health care systems. Cigarette smoking is the primary cause of COPD, and its progression can lead to irreversible lung damage.

In addition to the persistent symptoms, acute COPD can result in hospitalization and a rapid decline in lung function. This underscores the importance of prevention, early detection, and precise and effective management, which aligns with this year’s World COPD theme: “Short of Breath, Think COPD.”

Blood counts betray COPD exacerbation risks

The HKUMed research team reviewed local research advances over the past year, focusing on methods to predict acute COPD exacerbations. A key finding indicates that measuring blood eosinophil counts—a specific type of white blood cell—can help identify patients at risk of acute COPD exacerbations. While international guidelines recommend measuring eosinophil levels at a single time point, the team found that variability of blood eosinophil counts between stable periods and acute exacerbations was associated with a higher risk of future exacerbations.

“These findings suggest that patients’ risk profiles could be stratified by measuring blood eosinophil counts at different time points, both during stable state and at the time of exacerbation, which can provide a more accurate prediction of exacerbation risk,” said Dr. Herbert Kwok Wang-chun, Clinical Assistant Professor, Department of Medicine, School of Clinical Medicine, HKUMed, who led the study.

Bacteria in sputum linked to COPD exacerbation risks

In addition to blood parameters, sputum analysis can be used to predict acute COPD exacerbations. The findings reveal that approximately 10% of COPD patients have Pseudomonas aeruginosa colonization in their airways, as detected through sputum analysis. This bacterial presence significantly elevates the risk of future exacerbations, underscoring the importance of including sputum analysis in clinical management for COPD patients.

The newly released Global Initiative for Chronic Obstructive Lung Disease Report 2026 once again underscores the importance of acute exacerbations and introduces revised patient classification criteria. In the 2025 edition, patients who experienced at least two moderate exacerbations or one severe exacerbation in the previous year were classified as high risk.

In contrast, the 2026 edition redefines high-risk patients to include those with at least one moderate exacerbation in the previous year. This update highlights the importance of exacerbations in COPD management and reminds clinicians to factor in every exacerbation when developing treatment plans. Early identification of high-risk patients is essential for developing effective therapeutic strategies.

Dr. Kwok said, “Our team is actively pursuing further research into COPD phenotyping and personalized treatment. We are also leading a multi-national multi-center study involving eight countries and regions in the Asia-Pacific to further refine personalized treatment strategies for COPD.

“Through these advancements, we aim to enhance understanding of COPD and its exacerbations, which are both treatable and preventable,” added Dr. Kwok.

More information:
Wang Chun Kwok et al, Differences in Blood Eosinophil Level During Stable Disease and During Exacerbation of COPD and Exacerbation Risks, Lung (2025). DOI: 10.1007/s00408-025-00792-9


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