Blood eosinophils as predictor of outcomes in patients hospitalized for COPD exacerbations: a prospective observational study

Purpose In the present prospective multicentre observational study, we evaluated the potential role of blood eosinophils on the outcomes of patients hospitalized for COPD exacerbations. Material and methods Consecutive patients >40 years with a previous COPD diagnosis were recruited. Blood eosinophils were measured on admission prior to the initiation of treatment and were evaluated in three groups (<50, 50-149 and >= 150 cells/mu L). Patients received standard care and were followed up for a year. Results A total of 388 patients were included (83.5% male, mean age 72 years). Patients with higher blood eosinophils had less dyspnoea (Borg scale), lower C-reactive protein (CRP) and higher PaO2/FiO(2) (partial pressure for oxygen/fraction of inhaled oxygen), and were discharged earlier (median 11 vs. 9 vs. 5 days for patients with <50, 50-149 and >= 150 cells/mu L, respectively). Patients with <50 cells/mu L presented higher 30-day and 1-year mortality, whereas there were no differences in moderate/severe COPD exacerbations between the three groups. In a post hoc analysis, treatment with inhaled corticosteroids as per physicians' decision was associated with better exacerbation prevention during follow-up in patients with >= 150 cells/mu L. Conclusions Higher blood eosinophils were associated with better outcomes in hospitalized COPD patients, further supporting their use as a prognostic biomarker.