[1] Sichuan Univ, West China Hosp, Gen Practice Ward, Int Med Ctr Ward, Chengdu, Peoples R China
[2] Sichuan Univ, West China Hosp, Natl Clin Res Ctr Geriatr, Chengdu, Peoples R China
[3] Chengdu Med Coll, Dept Gastroenterol, Affiliated Hosp 1, Chengdu, Peoples R China
[4] Sichuan Univ, West China Hosp, Dept Period Press, Chengdu, Peoples R China
[5] Sichuan Univ, West China Hosp, Natl Clin Res Ctr Geriatr, Chengdu, Peoples R China