High eosinophil blood counts are associated with a shorter length of hospital stay in exacerbated COPD patients - a retrospective analysis

In COPD, the course of the disease including morbidity and mortality is strongly associated with severe exacerbations. The current GOLD recommendations emphasize blood eosinophil counts as a marker for responsiveness to inhaled corticosteroids (ICS). Retrospective analyses from randomized clinical trials indicate a favorable response to systemic corticosteroids in exacerbated COPD patients with blood eosinophils > 2%, however data outside clinical trials are scarce. We retrospectively evaluated data from 1007 cases of patients who were admitted to the University Medical Center Marburg between 01/2013 and 12/2018. All patients had been diagnosed with an acute exacerbation of COPD (ICD-10 J44.0/J44.1). Our analysis was based on a subgroup of 417 patients in whom a full blood cell count was obtained at the day of admission. Patients were predominantly male (63.3%), had a median age of 74 years (IQR 65 years - 83 years) and a median FEV1 of 1.03 l (42.6% predicted). We compared the hospital length of stay and other outcome parameters using established thresholds for the eosinophil blood cell count (100 and 300 eosinophils/μl and 2%). Patients with low eosinophils (