Persistent Blood Eosinophilia and Eosinopenia: Relationship with Outcomes in Bronchiectasis

Area of Science:

• Pulmonology
• Clinical Medicine
• Respiratory Diseases

Background:

• Blood eosinophil counts (BEC) correlate with bronchiectasis severity and treatment response.
• Baseline BEC is typically used, but BEC levels can fluctuate over time.
• Understanding dynamic BEC changes is vital for accurate patient assessment.

Purpose of the Study:

• To investigate the association between persistent eosinophilia/eosinopenia and clinical outcomes in bronchiectasis.
• To analyze how sustained high or low BEC levels impact disease severity and exacerbation frequency.
• To determine if monitoring temporal BEC changes offers better prognostic value than baseline BEC alone.

Main Methods:

• A multicentre, prospective observational study involving 43 Spanish centers (RIBRON registry).
• Included patients with at least two annual BEC measurements, excluding those with asthma or on anti-eosinophil therapy.
• Defined persistent eosinophilia (≥300 cells/μL) and eosinopenia (<100 cells/μL) based on three yearly BEC measures.

Main Results:

• 502 patients with at least three BEC measures were analyzed.
• Persistent eosinophilia was observed in 57.7% and persistent eosinopenia in 56.6% of relevant patients.
• Persistent eosinophilia was linked to greater disease severity and more frequent/severe exacerbations compared to non-persistent eosinophilia and persistent/non-persistent eosinopenia.

Conclusions:

• While baseline eosinopenia suggested higher severity, persistent eosinophilia indicated worse outcomes than persistent eosinopenia.
• Temporal monitoring of blood eosinophil counts is important for managing bronchiectasis.
• Dynamic BEC assessment provides critical insights into disease progression and exacerbation risk.