Eosinophilic Heterogeneity in COPD: How Stable Is the Eosinophilic Phenotype?

This study evaluated long-term variability in blood eosinophil counts in COPD patients from the EXCEL cohort. Blood eosinophil levels showed substantial fluctuation over time, with only a small proportion of patients demonstrating persistent eosinophilia across repeated stable visits, while a larger group displayed intermittent elevations or eosinophilia limited to exacerbations. These findings highlight that persistent eosinophilia is uncommon and that eosinophilic exacerbators represent a distinct subgroup, underscoring the need for refined phenotyping beyond a single blood eosinophil measurement to better inform targeted and biologic therapies in COPD.