[1] Harbin Med Univ, Canc Hosp, Dept Internal Med, 150 Haping ST, Harbin 150081, Heilongjiang, Peoples R China
[2] Harbin Med Univ, Affiliated Hosp 2, Dept Geriatr, Harbin 150086, Heilongjiang, Peoples R China
[3] Univ Texas Southwestern Med Ctr Dallas, Dept Internal Med, Dallas, TX 75390 USA