Blood Eosinophil Count and Hospital Readmission in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Matthew J Hegewald; Benjamin D Horne; Frank Trudo; James L Kreindler; Yen Chung; Susan Rea; Denitza P Blagev

doi:10.2147/COPD.S251115

Blood Eosinophil Count and Hospital Readmission in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Int J Chron Obstruct Pulmon Dis. 2020 Oct 23:15:2629-2641. doi: 10.2147/COPD.S251115. eCollection 2020.

Authors

Matthew J Hegewald^{1

2}, Benjamin D Horne^{3

4}, Frank Trudo⁵, James L Kreindler⁵, Yen Chung⁵, Susan Rea⁶, Denitza P Blagev^{1

2}

Affiliations

¹ Pulmonary and Critical Care Medicine Division, Intermountain Medical Center, Murray, UT, USA.
² Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, UT, USA.
³ Intermountain Heart Institute at Intermountain Healthcare, Salt Lake City, UT, USA.
⁴ Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA.
⁵ Health Economics Outcomes Research, AstraZeneca, Wilmington, DE, USA.
⁶ Enterprise Analytics, Intermountain Healthcare, Salt Lake City, UT, USA.

Abstract

Purpose: This retrospective, observational cohort study investigated the association of blood eosinophil counts within 1 week of hospitalization for acute exacerbation of COPD (AECOPD) with subsequent risk of all-cause and COPD-related readmission from a large integrated health system.

Patients and methods: Electronic medical records were extracted for index hospitalization for AECOPD at all Intermountain Healthcare hospitals. The primary outcome was the relationship of blood eosinophil count to 30-day all-cause readmission; secondary outcomes were 60-day, 90-day, and 12-month all-cause readmission, COPD-related readmission, and empiric derivation of the eosinophil count with the highest area under the curve (AUC) for predicting 30-day all-cause readmission.

Results: Of 2445 included patients, 1935 (79%) had a blood eosinophil count <300 cells/µL and 510 (21%) had a count ≥300 cells/µL. Using a 300-cells/μL threshold, there was no significant difference between high and low eosinophil groups in 30-day (odds ratio [OR]=1.05, 95% confidence interval [CI]=0.75-1.47) or 60-day (OR=1.15, 95% CI=0.88-1.51) all-cause readmissions. However, patients with greater (versus lesser) eosinophil counts had increased 90-day and 12-month all-cause readmissions (OR=1.35, 95% CI=1.06-1.72, and OR=1.32, 95% CI=1.07-1.62). COPD-related readmission rates were significantly greater for patients with greater (versus lesser) eosinophil counts at 30, 60, and 90 days and 12 months (OR range=1.52-1.97). A total of 70 cells/µL had the most discriminatory power to predict 30-day all-cause readmission (highest AUC).

Conclusion: Eosinophil counts in patients with COPD were not associated with a difference in 30-day all-cause readmissions. However, greater eosinophil counts were associated with increased risk of all-cause readmission at 90 days and 12 months and COPD-related readmission at 30, 60, and 90 days and 12 months. Patients with eosinophils <70 cells/μL had the lowest risk for 30-day all-cause readmission. Blood eosinophils in patients hospitalized with AECOPD may be a useful biomarker for the risk of hospital readmission.

Keywords: AECOPD; biomarkers; electronic medical records; eosinophils; phenotype.

Publication types

Observational Study

MeSH terms

Disease Progression
Eosinophils*
Humans
Leukocyte Count
Patient Readmission
Pulmonary Disease, Chronic Obstructive* / diagnosis
Pulmonary Disease, Chronic Obstructive* / therapy
Retrospective Studies

Grants and funding

This study was funded by AstraZeneca (Wilmington, DE, USA).