1. Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine; China-Japan Friendship Hospital; Beijing P.R. China
2. National Clinical Research Center for Respiratory Diseases; Beijing P.R. China
3. Graduate School of Peking Union Medical College; Chinese Academy of Medical Science and Peking Union Medical College; Beijing P.R. China
4. Data and Project Management Unit, Institute of Clinical Medical Sciences; China-Japan Friendship Hospital; Beijing P.R. China
5. Beijing Institute of Respiratory Medicine; Beijing Chao-Yang Hospital, Capital Medical University; Beijing P.R. China
6. Department of Respiratory Medicine; Capital Medical University; Beijing P.R. China