Hector Ortega, Jean-Pierre Llanos, Marie-Hélène Lafeuille, Guillaume Germain, Mei Sheng Duh, Christopher F Bell, Susan R Sama, Beth Hahn

Based on blood and sputum samples, up to 40% of patients with COPD have eosinophilic inflammation; however, there is little epidemiology data characterizing the health care burden within this sub-population. Given that COPD-attributable medical costs in the USA are predicted to approach $50 billion by 2020, we analyzed the effect of blood eosinophil counts and exacerbations on health care resource utilization and costs. This cross-sectional study used electronic medical records and insurance claims data from the Reliant Medical Group (January 2011-December 2015). Eligible patients were ≥40 years of age, continuously enrolled during the year of interest (2012, 2013, 2014, or 2015), had ≥1 COPD-related code in the preceding year, and documented maintenance therapy use. Patients with ≥1 blood eosinophil count recorded were stratified into 2 cohorts: <150 cells/µL and ≥150 cells/µL. Endpoints included demographics, clinical characteristics, health care resource utilization, and costs. The impact of blood eosinophil count and exacerbation patterns on health care resource utilization and costs was assessed with multivariate analyses. On average, 2,832 eligible patients were enrolled annually, of whom ~28% had ≥1 eosinophil count recorded during the year. The ≥150 cells/µL cohort had numerically higher all-cause and COPD-related health care resource utilization and cost each year compared with the <150 cells/µL cohort, but varied by service and year. Among patients with exacerbations, the ≥150 cells/µL cohort exhibited significantly higher COPD-related costs compared with the <150 cells/µL cohort. Blood eosinophil counts may be a useful biomarker for burden of disease in a subgroup of patients with COPD.