Evaluation of exacerbations and blood eosinophils in UK and US COPD populations

Blood eosinophil counts and history of exacerbations have been proposed as predictors of patients with chronic obstructive pulmonary disease (COPD) who may benefit from triple therapy (inhaled corticosteroid, long-acting β₂-agonist and long-acting muscarinic antagonist).

In a retrospective cohort analysis we examined the profiles of COPD patients from the UK Clinical Practice Research Datalink (CPRD) and US Optum Clinformatics™ Data Mart (Optum) databases with reference to exacerbation frequency and blood eosinophil distribution.

Of the 31,437 (CPRD) and 383,825 (Optum) patients with COPD, 15,364 (CPRD) and 139,465 (Optum) met the eligibility criteria and were included. Among patients with ≥2 exacerbations and available eosinophil counts in the baseline period (CPRD, n = 3089 and Optum, n = 13414), 17.0 and 13.3% respectively had eosinophil counts ≥400 cells/μL. Patients with ≥2 exacerbations or eosinophil count ≥400 cells/μL during first year, exacerbated at least once (CPRD, 82.8% vs Optum, 80.6%) or continued to have eosinophil count ≥300 cells/μL (76.8% vs 76.5%), respectively in the follow-up year. In both years, a higher variability in the number of exacerbations and eosinophil count was observed in patients with one exacerbation and eosinophil counts between 300 and 400 cells/μL; patients with eosinophil count < 150 cells/μL had the lowest variability. Approximately 10% patients had both ≥2 exacerbations and eosinophil count ≥300 cells/μL across the databases.

A high variability in blood eosinophil counts over two consecutive years was observed in UK and US patients with COPD and should be considered while making treatment decisions. A small proportion of COPD patients had frequent exacerbations and eosinophil count ≥300 cells/μL.