The Journal of Medical Investigation
Online ISSN : 1349-6867
Print ISSN : 1343-1420
ISSN-L : 1343-1420
The prevalence and clinical features of asthma-COPD overlap (ACO) definitively diagnosed according to the Japanese Respiratory Society Guidelines for the Management of ACO 2018
Kenta YamamuraJohsuke HaraTakafumi KobayashiNoriyuki OhkuraMiki AboKyota AkasakiSyunichi NomuraMizuki YuasaKeigo SaekiNanao TeradaHiroki MatsuokaYuichi TamboShingo NishikawaTakashi SoneHideharu KimuraKazuo Kasahara
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2019 Volume 66 Issue 1.2 Pages 157-164

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Abstract

Background Asthma-COPD overlap (ACO) is a disease that shares clinical features of both asthma and COPD. The purpose of this study is to investigate the prevalence and clinical features of ACO. Methods We retrospectively reviewed data for 170 patients with persistent airflow limitation and diagnosed them according to “The Japanese Respiratory Society Guidelines for the Management of ACO 2018”. Results Of the 170 patients, 111 were diagnosed as follows : COPD (74 patients, 66.6%), ACO (34 patients, 30.6%), and asthma (3 patients, 2.8%). There was no significant difference in clinical features between ACO and COPD patients. The following pulmonary function tests were significantly lower in ACO than in COPD patients : forced expiratory volume in 1 second/forced vital capacity, peak expiratory flow, maximal mid-expiratory flow, and the maximum expiratory flow at 50%and75%. The following respiratory impedance parameters were significantly higher in ACO than in COPD patients : respiratory resistance (Rrs) at 5 Hz (R5), Rrsat 20 Hz (R20), R5-R20, and low-frequency reactance area. Conclusions About 30% of patients with persistent airflow limitation were diagnosed with ACO. ACO patients had lower lung function and higher respiratory impedance compared with COPD patients. J. Med. Invest. 66 : 157-164, February, 2019

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© 2019 by The University of Tokushima Faculty of Medicine
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