title: Confounding factors in observational hip fracture studies.
authors.affiliation: Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China. xuefushan@aliyun.com.
authors.forename: F S
authors.initials: FS
authors.lastname: Xue
authors.forename: S Y
authors.initials: SY
authors.lastname: Wang
authors.forename: X L
authors.initials: XL
authors.lastname: Cui
mesh_terms: D000758:Anesthesia; D005260:Female; D006620:Hip Fractures / Q000601:surgery*; D006801:Humans; D008297:Male