1. Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
2. Chinese Evidence-Based Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
3. Department of Endocrinology and Metabolism, Shanghai Diabetes Institute, Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, People's Republic of China.