The acute wheezy adult with airways disease in the emergency department: a retrospective case-note review of exacerbations of COPD.

Introduction: There has been an increase in interest in the peripheral blood eosinophil count as a biomarker in COPD. Few studies have examined the eosinophil count in patients attending the emergency department (ED) with acute exacerbations of COPD (AECOPD). We investigated the relationship between the blood eosinophil and other variables collected routinely at ED presentation and outcomes. Methods: Retrospective case note review of patients attending the ED with an AECOPD over 18 months. Demographic, clinical and pharmacological data were analyzed at the time of presentation, and clinical outcomes relating to hospital admission, length of hospital stay and mortality were investigated. Results: There were 743 AECOPD index events in 537 patients. Over half (57%) of all attendees were admitted to hospital. They were older, reported an increased number of exacerbations and higher levels of total leukocytes and neutrophils. Length of stay was shorter in patients with a blood eosinophil count ≥2% compared to <2% (median (IQR) 3 days (1-7) vs 4 days (2-8) respectively, p<0.05). Length of stay correlated with peripheral blood neutrophils (r=0.12, p=0.021), peripheral blood absolute and relative eosinophils (r=-0.12, p=0.024 and r=-0.11, p=0.035, respectively) and CRP (r=0.16, p=0.027). Non-eosinophilic AECOPD were associated with an increased risk of mortality during an exacerbation (χ2 5.9, OR 3.08, 95% CI 1.19-7.96, p=0.015). Conclusion: In exacerbations of COPD presenting to ED, a higher blood eosinophil count is associated with a shorter length of stay and reduced mortality.