Predictors of asthma exacerbation between high and low blood eosinophil counts.

Abstract

Background: Despite treatment advances, managing asthma remains challenging owing to variability in response across different type 2 inflammation phenotypes. We aimed to compare the differences in pre-treatment profiles related to 12-month asthma exacerbation in patients with baseline high and low blood eosinophil count (BEC) levels.

Methods: This study included 438 and 231 patients with asthma with pre-treatment BEC levels >300 cells·μL^-1 (high BEC) and <150 cells·μL^-1 (low BEC), respectively, and no history of systemic corticosteroid use. 40 pre-treatment variables were collected and exacerbation occurrences were tracked over 12 months. The least absolute shrink and selection operator (LASSO) regression was applied to identify key variables for predicting exacerbation occurrences in the two BEC groups.

Results: Baseline characteristics, including impaired lung function, female sex and sensitivity to stress as an asthma trigger were important predictors of exacerbation in both BEC groups. Significant characteristics related to exacerbation in the high-BEC group included high pre-treatment BEC levels, history of smoking, sensitivity to tobacco smoke and allergic-related conditions. In contrast, key characteristics associated with exacerbation in the low-BEC group included high baseline peripheral neutrophil counts, current smokers, history of tuberculosis and the use of long-acting β2 agonists plus long-acting muscarinic agonists. The prediction model for 12-month exacerbation using baseline characteristics had stronger predictive power in the low-BEC group than the high-BEC group.

Conclusion: The exacerbation profiles of patients with asthma with high and low pretreatment BEC levels share some common characteristics despite substantial differences.