1. Anhui Evidence-based Medicine Center; Anhui Provincial Hospital; Hefei 230001 China
2. Chinese Evidence-based Medicine Center/Chinese Cochrane Center, West China Hospital; Sichuan University; Chengdu 610041 China
3. West China Medical School, West China Hospital; Sichuan University; Chengdu 610041 China
4. Department of Geriatrics; Anhui Provincial Party Committee Hospital; Hefei 230001 China