Prevalence of blood eosinophilia in hospitalized patients with acute exacerbation of COPD.

In this cohort of 3084 patients hospitalized for acute exacerbation of COPD (AECOPD), we found that 17% had blood eosinophilia (≥300 cells/μL); the use of an alternative cut-off level (≥2%) demonstrated that 40% had elevated eosinophil count. Patients with eosinophilia had higher frequency of readmission for AECOPD during 1-year follow-up period. This is the first study to investigate the prevalence of eosinophilia among inpatients with AECOPD--the population with the highest morbidity and health-care utilization.