Blood Eosinophil Levels and Prognosis of Hospitalized Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Studies about the clinical significance of high eosinophil levels in chronic obstructive pulmonary disease (COPD) are conflicting, and it has been less studied in hospitalized patients with acute exacerbation of COPD (AECOPD).This study was to examine blood eosinophil levels in relation to the prognosis of hospitalized patients with AECOPD. This was a retrospective cohort study of patients with AECOPD as their primary diagnosis and admitted to Beijing Shijitan Hospital, Capital Medical University, from January 2010 to December 2016. The patients were assigned according to the count of eosinophil in peripheral blood at their first hospitalization. Patients were grouped as ≤100, 100–300, and ≥300 eosinophils/µL of peripheral blood. The use of glucocorticoids, duration of hospitalization, in-hospital mortality, and re-hospitalization were examined. Compared with the 100–300 eosinophils/µL group, the ≤100 eosinophils/µL group showed higher frequencies of fever, respiratory failure, and the use of systemic glucocorticoids. Eosinophil counts were not associated with in-hospital mortality and duration of hospitalization. The multivariable analysis showed that GOLD3/4 (odds ratio (OR)=2.04, 95%CI: 1.20–3.44, P = 0.008), systemic glucocorticoids (OR=1.84, 95%CI: 1.41–2.98, P = 0.012), mechanical ventilation (OR=2.66, 95%CI: 1.36–5.18, P = 0.004), and acute exacerbation in the past year before hospitalization (OR=2.03, 95%CI: 1.27–3.23, P = 0.003) were independently associated with acute exacerbation within 1 year after discharge. Eosinophil count was not associated with acute exacerbation within 1 year after discharge. Peripheral blood eosinophil counts are not associated with the 1-year AECOPD prognosis.