Yoon, Jung-Ki, Lee, Jung-Kyu, Lee, Chang-Hoon, Hwang, Yong Il, Kim, Hyunkuk, Park, Dongil, Hwang, Ki-Eun, Kim, Sang-Heon, Jung, Ki-Suck, Yoo, Kwang Ha, Ra, Seung Won, and Kim, Deog Kyeom
Jung-Ki Yoon,1 Jung-Kyu Lee,2 Chang-Hoon Lee,1 Yong Il Hwang,3 Hyunkuk Kim,4 Dongil Park,5 Ki-Eun Hwang,6 Sang-Heon Kim,7 Ki-Suck Jung,3 Kwang Ha Yoo,8 Seung Won Ra,9 Deog Kyeom Kim2,10 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea; 2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea; 3Department of Internal Medicine, College of Medicine, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea; 4Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Republic of Korea; 5Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Republic of Korea; 6Department of Internal Medicine, Wonkwang University, School of Medicine, Iksan, Republic of Korea; 7Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea; 8Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea; 9Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea; 10Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of KoreaCorrespondence: Deog Kyeom KimDivision of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of KoreaTel +82-2-870-2228Fax +82-2-831-0714Email kimdkmd@snu.ac.krIntroduction: Blood eosinophils are a predictive marker for the use of inhaled corticosteroids (ICS). However, there is concern over whether a single measure of blood eosinophils is sufficient for outlining a treatment plan. Here, we evaluated the association between variability in blood eosinophils and the effects of ICS in stable COPD cohorts.Methods: COPD patients in the Korean COPD Subtype Study and the Seoul National University Airway Registry from 2011 to 2018 were analyzed. Based on blood eosinophils at baseline and at 1-year follow-up, the patients were classified into four groups with 250/μL as a cutoff value: consistently high (CH), consistently low (CL), variably increasing (VI), and variably decreasing (VD). We compared rates of acute exacerbations (AEs) according to ICS use in each group after calibration of severity using propensity score matching.Results: Of 2,221 COPD patients, 618 were analyzed and a total of 125 (20%), 355 (57%), 63 (10%), and 75 (12%) patients were classified into the CH, CL, VI, and VD groups, respectively. After calibration, we found that ICS users tended to have a lower AE rate in the CH group (RR 0.41, 95% CI 0.21– 0.74) and VI group (RR 0.45, 95% CI 0.22– 0.88), but not in the CL group (RR 1.42, 95% CI 1.08– 1.89) and VD group (RR 1.71, 95% CI 1.00– 2.96).Conclusion: More than one-fifth of patients had an inconsistent blood eosinophil level after the 1-year follow-up, and the AE-COPD rate according to ICS differed based on variability in eosinophils. Regular follow-up of blood eosinophils is required for COPD patients.Keywords: COPD, eosinophils, inhaled corticosteroids, acute exacerbations of COPD, COPD treatment