Risk of hospitalised bronchiectasis exacerbation based on blood eosinophil counts

Abstract

<p><strong>SETTING:</strong> There has been growing recognition on the importance of phenotyping of airway diseases. The eosinophilic phenotype was proposed in bronchiectasis; however, there has not been any evidence on its association with the risk of hospitalised bronchiectasis exacerbations.<br><br><strong>OBJECTIVE:</strong> To investigate the association between baseline blood eosinophil count (BEC) and bronchiectasis exacerbations requiring hospitalisation with validation by an independent cohort.<br><br><strong>DESIGN:</strong> This was a retrospective cohort study.<br><br><strong>RESULTS:</strong> Over a 24-month period, 37/318 (11.6%) study participants experienced an exacerbation requiring hospitalisation. The mean baseline serum eosinophil was 135 ± 92 cells/µL in those who had exacerbations, and 188 ± 161 cells/µL in those who did not. A serum eosinophil level of 250 cells/µL at stable state was the most significant cut-off for predicting hospitalised bronchiectasis exacerbation, which was validated by the independent cohort.<br><br><strong>CONCLUSIONS:</strong> Patients with BEC below 250 cells/µL at stable state are at increased risk of having hospitalised bronchiectasis exacerbations.<br></p>