A subset of patients with chronic obstructive pulmonary disease (COPD) demonstrates eosinophilic inflammation either in their sputum or blood. Previous studies regarding the association between increased blood eosinophils and poor readmission outcomes are conflicting.
Investigate outcomes following severe COPD exacerbations in patients with higher blood eosinophils.
With an observational study design, hospitalizations for severe COPD exacerbation were retrospectively gathered. Patient health data previous to and up to one year following the index hospitalization were included. Patients were stratified into the eosinophilic group if the blood eosinophil level on admission was ≥200 cells/μL and/or ≥2% of the total white blood cell count. Clinical outcomes were 12-month COPD-related readmission, 12-month all-cause readmission, length of stay, and time to COPD-related readmission. These outcomes were analysed using logistic, negative binomial, and Cox regression models.
A total of 167 patients were included: 55 with eosinophilia. Eosinophilia was associated with an increased risk of 12-month COPD-related readmission (OR 3.59 [1.65-7.82], p=0.0013), an increased risk of 12-month all-cause readmission (2.32 [1.10-4.92], p=0.0277), and a shorter time to first COPD-related readmission (HR 2.74 [1.56-4.83], p=0.0005). The length of stay was not statistically different between eosinophilic and non-eosinophilic patients. Sensitivity analyses using different eosinophilia definitions reveal a proportional increase in effect size with increasing eosinophil cell count definitions for predicting 12-month readmissions.
Blood eosinophils can be used as a biomarker in severe COPD exacerbations for predicting higher readmission rates.