Effect of Blood Eosinophil Counts on COPD Clinical Outcomes

Patients with chronic obstructive pulmonary disease (COPD) and low blood eosinophil counts had no change in exacerbations or survival compared with patients with typical counts, according to findings presented at the 2021 American Thoracic Society (ATS) International Conference, held virtually from May 14-19, 2021.

Researchers measured blood eosinophil counts in patients with COPD in the SPIROMICS cohort. Clinical outcome data were then used to determine associations between eosinophil counts and disease outcomes.

Among the 1414 participants with COPD in the SPIROMICS cohort, 485 were considered to have low blood eosinophil counts with 61 classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) group D and 929 had typical blood eosinophil counts with 124 classified as GOLD group D. Among the group of participants who had low blood eosinophil counts, there was a significantly higher proportion of current smokers and a lower frequency of reported childhood asthma. Participants with low blood eosinophil counts demonstrated a faster rate of decline of forced expiratory volume in 1 second (FEV₁; slope, -0.046 vs -0.038; P <.00001). When the 2 groups were compared in longitudinal analysis, there was no difference in the frequency of acute exacerbations, inhaled corticosteroid initiation, or mortality.  

“Our findings highlight the known interactions between low blood eosinophil counts, responsiveness to [inhaled corticosteroids], and smoking status, emphasizing the importance of adequate interpretation of the role of [blood eosinophil counts] in the evaluation and management of COPD,” the study authors wrote.  

Reference

Lemaster WB, Quibrera PM, Couper D, et al. Clinical implications of low absolute blood eosinophil count in the SPIROMICS COPD cohort. Presented at: the American Thoracic Society (ATS) International Conference 2021; May 14-19, 2021. Abstract A1245.