Clinical and Translational Research
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jul 6, 2020; 8(13): 2727-2737
Published online Jul 6, 2020. doi: 10.12998/wjcc.v8.i13.2727
Role of peripheral eosinophilia in acute exacerbation of chronic obstructive pulmonary disease
Chih-Wei Wu, Chou-Chin Lan, Po-Chun Hsieh, I-Shiang Tzeng, Yao-Kuang Wu
Chih-Wei Wu, Chou-Chin Lan, Yao-Kuang Wu, Division of Pulmonary Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan
Po-Chun Hsieh, Department of Chinese Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan
I-Shiang Tzeng, Department of Research, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan
Author contributions: Wu YK contributed to the study design and reviewed the manuscript; Tzeng IS and Lan CC analyzed the data. Wu CW contributed to data interpretation and manuscript writing; Hsieh PC contributed to data collection; Wu CW revised the paper.
Supported by Taipei Tzu Chi Hospital, No. TCRD-TPE-108-RT-4 and No. TCRD-TPE-108-4.
Institutional review board statement: The study was approved by Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation Institutional Review Board on September 2019 (protocol number 08-X-094).
Clinical trial registration statement: The study was conducted retrospectively.
Informed consent statement: The informed consent to the study is not required because the clinical data were anonymous.
Conflict-of-interest statement: All authors declared no conflict-of-interest.
Data sharing statement: The authors could obtain the data under the permission of the corresponding author (ykwutzhtpe@gmail.com).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Yao-Kuang Wu, MD, Attending Doctor, Division of Pulmonary Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 289 Jianguo Road, Xindian District, New Taipei City 23142, Taiwan. drbfci@yahoo.com.tw
Received: January 16, 2020
Peer-review started: January 16, 2020
First decision: April 14, 2020
Revised: April 26, 2020
Accepted: June 29, 2020
Article in press: June 29, 2020
Published online: July 6, 2020
ARTICLE HIGHLIGHTS
Research background

The eosinophilic phenotype accounts for 20%-40% of chronic obstructive pulmonary disease (COPD) exacerbations. The peripheral blood eosinophil count (PBEC) is a well-established predictor of the length of hospital stay, steroid response, prognosis, and readmission rate. Additionally, previous research supported the tendency of non-infectious inflammation in the eosinophilic group.

Research motivation

Some characteristics of patients with eosinophilic COPD exacerbation, such as demographics, comorbidities, lung function, etc., are inconsistent across studies. Studies on the role of eosinophilia primarily focused on the Caucasian race. A few studies investigated eosinophilic COPD exacerbation in Asian populations.

Research objectives

We aimed to study the role of peripheral eosinophilia in hospitalized patients with COPD exacerbation in Taiwan.

Research methods

From January 2014 to May 2017, patients with COPD exacerbation hospitalized in Taipei Tzu Chi Hospital were retrospectively stratified into two groups according to their peripheral eosinophil count: The EOS group (eosinophil count ≥ 2%) and the non-EOS group (eosinophil count < 2%).

Research results

A total of 625 patients were recruited, with 176 patients (28.2%) in the eosinophilic group. The eosinophilic group showed a lower prevalence of infection, lower cumulative doses of prednisolone equivalents, shorter length of hospital stay, and higher number of COPD-related readmissions than the non-EOS group. There were significantly linear correlations between eosinophil percentage and number of readmissions and between eosinophil percentage and length of hospital stay (P < 0.001, Pearson's r = 0.147; P = 0.031, Pearson's r = -0.086, respectively).

Research conclusions

The PBEC had a positive linear correlation with the number of readmissions. Eosinophilia is a predictor of steroid response and non-infectious inflammation.

Research perspectives

We should strengthen the management of comorbidities and optimization of inhaled medications to reduce the high readmission risk in the EOS group. Routine survey of PBEC for acute COPD exacerbation is warranted to reduce the notorious side effects of steroids. With meticulous exclusion of possible infections, we could avoid empirical antibiotic therapy since the EOS group has a non-infectious nature. Effective target therapy for eosinophilic COPD exacerbation is urgently required.