Blood Eosinophilia and Its Stability in Hospitalized COPD Exacerbations are Associated with Lower Risk of All-Cause Mortality

Ying Zhang; Li-Rong Liang; Shu Zhang; Yong Lu; Yang-Yu Chen; Huan-Zhong Shi; Ying-Xiang Lin

doi:10.2147/COPD.S245056

Blood Eosinophilia and Its Stability in Hospitalized COPD Exacerbations are Associated with Lower Risk of All-Cause Mortality

Int J Chron Obstruct Pulmon Dis. 2020 May 19:15:1123-1134. doi: 10.2147/COPD.S245056. eCollection 2020.

Authors

Ying Zhang^#¹, Li-Rong Liang^#², Shu Zhang¹, Yong Lu¹, Yang-Yu Chen¹, Huan-Zhong Shi¹, Ying-Xiang Lin¹

Affiliations

¹ Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine and Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, People's Republic of China.
² Clinical Epidemiology and Tobacco Dependence Treatment Research Department, Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, People's Republic of China.

^# Contributed equally.

Abstract

Purpose: Peripheral blood eosinophilic counts are susceptible to many factors and have variability over time. There are limited studies on association of blood eosinophilia with long-term mortality of chronic obstructive pulmonary disease (COPD) patients and these results remain controversial. Our aims were to explore the association of blood eosinophilia at index hospitalization and stability of blood eosinophilia stability over 5 years with all-cause mortality of patients hospitalized for acute exacerbation of COPD (AECOPD).

Patients and methods: Eight hundred twenty-nine patients hospitalized for AECOPD between 2013 and 2014 were included in this study and grouped into two groups according to blood eosinophil with 150 cells/μL used as the cutoff value to form eosinophilic and non-eosinophilic groups. Two hundred forty-one COPD inpatients with at least three blood eosinophils measured from different hospitalizations were used for analysis of longitudinally eosinophilic stability and divided into three groups according to the same cutoff value: predominantly (PE), intermittently (IE) and rarely (RE) eosinophilic groups. Cox regression analysis was used to determine the association of blood eosinophilia and all-cause mortality.

Results: In patients hospitalized for AECOPD, 261 (31.5%) at baseline and 41 (17%) based on at least three measurements of blood eosinophils had increased blood eosinophils. For all-cause mortality, eosinophilic COPD patients at index hospitalization had a lower all-cause mortality compared with non-eosinophilic COPD patients (hazard ratio 0.77, 95% confidence interval 0.6-0.99, P=0.04). In patients readmitted for AECOPD by longitudinal eosinophil stability, with the RE group used as reference, the PE group was associated with a lower all-cause mortality of AECOPD patients (hazard ratio 0.43, 95% confidence interval 0.22-0.85, P=0.016), compared to the IE group (hazard ratio 0.72, 95% confidence interval 0.47-1.11, P=0.133).

Conclusion: Patients with increased eosinophils (using eosinophil 150 cells/μL as a cutoff value), especially predominantly increased eosinophil levels based on multiple measurements, had a lower risk of all-cause mortality. Blood eosinophilia can be used as a biomarker in hospitalized COPD exacerbations for predicting the risk of all-cause mortality.

Keywords: acute exacerbation; blood eosinophilia; chronic obstructive pulmonary disease; mortality.

MeSH terms

Disease Progression
Eosinophilia* / diagnosis
Eosinophils
Humans
Leukocyte Count
Pulmonary Disease, Chronic Obstructive* / diagnosis
Pulmonary Disease, Chronic Obstructive* / therapy

Grants and funding

This work was supported by the National Key R&D Program of China (2016YFC1303900), the Beijing Municipal Administration of Hospitals’ Mission Plan, the People's Republic of China (No. SML20150301), Capital’s Funds for Health Improvement and Research (No. CFH2016-4-1062) and Chinese Medical Association Chronic Respiratory Disease Fund (No. CRD 08020440122).