Eosinophil-Guided Therapy In Chronic Obstructive Pulmonary Disease: Evaluating Blood Eosinophils As Predictors Of Inhaled-Corticosteroids Response

Abstract

Background-Aim:
Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and is characterized by persistent airflow limitation and recurrent exacerbations. Although inhaled corticosteroids (ICS) are recommended for patients with frequent exacerbations, the response to therapy varies. Blood eosinophil count has emerged as a potential biomarker for identifying patients who may benefit from ICS-containing regimens. This study evaluated the role of baseline blood eosinophil count as a predictor of response to ICS therapy in COPD.

Materials–Methods:
This prospective observational study was conducted at the Department of Pulmonary Medicine, Sree Balaji Medical College & Hospital, Chennai, India, from August 2024 to March 2026. A total of 156 patients with spirometry-confirmed COPD receiving ICS-containing therapy were included. Patients were categorized into three groups based on baseline blood eosinophil count: <100, 100–300, and >300 cells/µL. Clinical evaluation included CAT score, mMRC dyspnea scale, spirometry, and exacerbation history. Patients were followed for 6 months to assess changes in lung function, symptoms, and exacerbation frequency. Data were analyzed using SPSS version 26.0 with p <0.05 considered statistically significant.

Results:
The mean age of participants was 62.1 ± 8.9 years, with 74.4% males. Patients with eosinophil counts >300 cells/µL showed significantly greater improvement in FEV₁ compared with the other groups (p <0.01). Greater reductions in CAT scores and lower exacerbation rates were also observed in the high eosinophil group (p <0.05). Baseline eosinophil count >300 cells/µL was identified as an independent predictor of improved response to ICS therapy.

Conclusion:
Baseline blood eosinophil count is a useful biomarker for predicting response to ICS therapy in COPD. Higher eosinophil levels are associated with improved lung function, better symptom control, and reduced exacerbations, supporting eosinophil-guided COPD management.