[1] Lanzhou Univ, Clin Med Coll 2, Lanzhou, Peoples R China
[2] Lanzhou Univ, Publ Hlth Sch, Lanzhou, Peoples R China
[3] Jingtaixian Hosp Tradit Chinese Med, Lanzhou, Peoples R China
[4] Gansu Univ Chinese Med, Lanzhou, Peoples R China
[5] Gansu Prov Hosp, Inst Clin Res & Evidence Based Med, Lanzhou, Peoples R China
[6] McMaster Univ, Hlth Res Methodol, Dept Hlth Res Methods Evidence & Impact, Hamilton, ON, Canada