1. Evidence-Based Medicine Center, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, P. R. China
2. The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300073, P. R. China
3. The Second Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300150, P. R. China
4. Department of Respiratory Diseases, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, P. R. China