[1] Cent South Univ, Xiangya Hosp 2, Dept Geriatr, Changsha, Hunan, Peoples R China
[2] Cent South Univ, Dept Clin Lab, Xiangya Hosp, Changsha, Hunan, Peoples R China
[3] Cent South Univ, Dept Clin Med, Xiangya Med Sch, Changsha, Hunan, Peoples R China
[4] Univ Alabama Birmingham, Dept Med, Div Pulm Allergy & Crit Care Med, Birmingham, AL 35294 USA