1. Lanzhou University; Evidence-Based Medicine Center, School of Basic Medical Sciences; No. 199, Donggang West Road Lanzhou City Gansu China 730000
2. Chinese Academy of Medical Sciences; Institute of Dermatology; Nanjing China 210042
3. Lanzhou University, Second Hospital; No. 82, Cui Ying Men Street Lanzhou City Gansu China 730030
4. Lanzhou University; The Second Clinical College of Lanzhou University; 222 Tianshui Southern Road Lanzhou City Gansu Province China 730000
5. West China Hospital, Sichuan University; Chinese Cochrane Centre; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041