1. Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China‑Japan Friendship Hospital, Beijing 100029, P.R. China
2. National Clinical Research Center for Respiratory Diseases, Beijing 100029, P.R. China
3. Department of Pulmonary and Critical Care Medicine, Kunming Municipal Hospital of Traditional Chinese Medicine, Kunming, Yunnan 650051, P.R. China