Blood Eosinophil Count, Disease Severity, and Exacerbation Risk in Korean Patients with Bronchiectasis: A...

Peripheral blood eosinophil count has been associated with bronchiectasis outcomes, but findings are inconsistent. Its role in acute exacerbations among Korean patients remain unclear.

This study retrospectively evaluated 492 patients with bronchiectasis at a tertiary hospital in Korea between 2014 and 2021. Using a negative binomial regression model adjusted for follow-up duration, we evaluated the association between peripheral eosinophil counts and acute exacerbations in Korean patients with bronchiectasis.

Among the 492 patients, 190 (38.6%) were categorized into the lower eosinophilic group, 221 (44.9%) into the normal eosinophilic group, and 80 (16.2%) into the higher eosinophilic group. No significant differences were observed across eosinophilic groups in terms of hospitalization within one year, BSI scores, or FACED scores (all p > 0.05). In the parsimonious negative binomial regression analysis with false discovery rate (FDR) correction, oral corticosteroid use (IRR = 2.26; 95% CI: 1.46-3.52; FDR p = 0.001), older age (IRR = 1.03; 95% CI: 1.01-1.04; FDR p = 0.002), and lower FEV1 % predicted (IRR = 0.98; 95% CI: 0.97-0.99; FDR p < 0.001) were identified as independent risk factors for acute exacerbations.

There was no significant association between peripheral blood eosinophil counts and either acute exacerbations or disease severity in Korean patients with bronchiectasis. In contrast, older age, lower lung function (FEV1 % predicted), and the use of oral corticosteroids were identified as independent risk factors for acute exacerbations. These findings underscore the importance of considering region-specific clinical and epidemiological factors in the management of bronchiectasis.