[1] Sichuan Univ, Dept Gen Pract, Int Med Ctr, Chengdu, Peoples R China
[2] Sichuan Univ, West China Hosp, Natl Clin Res Ctr Geriatr, Chengdu, Peoples R China
[3] Sichuan Univ, West China Hosp, Dept Med Adm, Chengdu, Peoples R China
[4] Sichuan Univ, Dept Anesthesiol, Chengdu, Peoples R China
[5] Chinese Acad Med Sci, Res Units West China, Chengdu, Peoples R China
[6] Sichuan Univ, Dept Period Press, Chengdu, Peoples R China
[7] Sichuan Univ, West China Hosp, Chinese Evidence Based Med Ctr, Chengdu, Peoples R China