title: Letter to the editor.
authors.affiliation: Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China.
authors.forename: Rao
authors.initials: R
authors.lastname: Sun
authors.forename: Wenyu
authors.initials: W
authors.lastname: Zhao
authors.forename: Hongliang
authors.initials: H
authors.lastname: Tian
authors.forename: Haijun
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Xiao
authors.forename: Jinhui
authors.initials: J
authors.lastname: Tian
authors.forename: Kehu
authors.initials: K
authors.lastname: Yang
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D010146:Pain / Q000175:diagnosis* / Q000453:epidemiology*; D010147:Pain Measurement / Q000379:methods*; D010808:Physical Examination / Q000379:methods*; D012720:Severity of Illness Index