title: Does Patient Sex Affect the Rate of Mortality and Complications After Spine Surgery? A Systematic Review.
abstract: BACKGROUND
  Available studies disagree regarding the influence of patient sex on mortality and complications after spine surgery. We sought to conduct a systematic review and pool the results of existing research to better understand this issue.
  
  
  OBJECTIVE
  We performed a systematic review to address two questions: (1) Does sex (male versus female) influence mortality after spine surgery? (2) Does sex impact the development of postoperative complications after spine surgery?
  
  
  METHODS
  This systematic review was performed through a query of PubMed using a structured search algorithm. Additional queries of Embase, SCOPUS, Web of Science, and the tables of contents of orthopaedic and neurosurgical journals were also conducted using search terms such as "sex factors", "male or female", "risk factors", and "spine surgery". Selected papers were independently abstracted by three of the authors (AJS, ENR, EIW) and pooling was performed. Our literature search returned 720 studies, of which 99 underwent full review. Of these, 50 were selected for final abstraction. The Cochrane Q test was used to assess study heterogeneity; significant study heterogeneity was present and so a random-effects model was used. A Harbord test was used to evaluate for the presence of publication bias; this analysis found no statistically significant evidence of publication bias.
  
  
  RESULTS
  Males were at increased odds of mortality after spine surgery (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.35-1.97; p<0.001). No differences between the sexes were identified for the odds of complications (OR, 1.04; 95% CI, 0.95-1.13; p=0.42).
  
  
  CONCLUSIONS
  Our results determined that males were at elevated odds of mortality but not of complications after spine surgery. These results should be used to inform preoperative discussion and decision-making at the time of surgical consent. Future work should be directed at determining the underlying factors responsible for increased mortality among males and prospective studies specifically designed to evaluate sex-based differences in outcomes after spine surgery.
  
  
  METHODS
  Level III, therapeutic study.
authors.affiliation: Department of Orthopaedic Surgery, University of Michigan, Ann Arbor Veterans Administration Hospital, 2800 Plymouth Road, Building 10, RM G016, Ann Arbor, MI, 48109, USA, ajschoen@neomed.edu.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Schoenfeld
authors.forename: Elyse N
authors.initials: EN
authors.lastname: Reamer
authors.forename: Emily I
authors.initials: EI
authors.lastname: Wynkoop
authors.forename: Hwajung
authors.initials: H
authors.lastname: Choi
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Bono
mesh_terms: D005260:Female; D054624:Health Status Disparities; D006801:Humans; D008297:Male; D016017:Odds Ratio; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000401:mortality*; D011183:Postoperative Complications / Q000401:mortality*; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013131:Spine / Q000601:surgery*; D016896:Treatment Outcome