1. West China Hospital, Sichuan University; Center of Geriatrics and Gerontology; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041
2. West China Hospital, Sichuan University; Chinese Clinical Trial Registry, Chinese Ethics Committee of Registering Clinical Trials; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041
3. West China Hospital, Sichuan University; Chinese Cochrane Centre, Chinese Evidence-Based Medicine Centre; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041