Introduction: Bronchiectasis is predominantly a neutrophilic disease, however approximately 20% of patients have elevated blood eosinophil counts (BEC). Eosinophilic inflammation has been linked to a higher risk of exacerbation.
Objectives: The aim of our study was to investigate whether there is a relationship between BEC, pulmonary function and exacerbations.
Methods: Retrospective observational single center study of adult patients followed in the Non-Cystic Fibrosis Bronchiectasis Center of Hospital de Santa Maria in Lisbon. Patients with known comorbid eosinophilic diseases such as asthma and allergic bronchopulmonary aspergillosis were excluded. BEC and spirometry were measured when clinically stable. Exacerbations within 1 year were registered.
Results: We included 75 patients, 57.3% female with a mean age of 53.2 ± 18.1 years. The main etiologies identified were idiopathic (45.3%), post-infectious (22.7%) and post-tuberculosis (13.3%). BEC (cells/uL) were <100 in 25.3% of patients, 100-299 in 54.7% and >300 in 20%. Patients with concomitant COPD had the highest mean BEC, 223 cells/uL. The mean FEV1 was 74.91%, and the subgroup with >300 cells/uL had a significant lower FEV1 (p=0.027). There was an average of 0.89 exacerbations, 17.9% severe. There was no significant difference in the overall or severe exacerbation rates between the 3 subgroups.
Conclusions: We didn?t find a correlation between BEC and the rate or the severity of exacerbations. However, higher levels of blood eosinophils were associated with COPD and poorer lung function. Our study was limited by the reduced sample of each BEC group.