title: Aspirin versus anticoagulation for prevention of venous thromboembolism major lower extremity orthopedic surgery: a systematic review and meta-analysis.
abstract: BACKGROUND
  Hip fracture surgery and lower extremity arthroplasty are associated with increased risk of both venous thromboembolism and bleeding. The best pharmacologic strategy for reducing these opposing risks is uncertain.
  
  
  OBJECTIVE
  To compare venous thromboembolism (VTE) and bleeding rates in adult patients receiving aspirin versus anticoagulants after major lower extremity orthopedic surgery.
  
  
  METHODS
  Medline, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library through June 2013; reference lists, ClinicalTrials.gov, and scientific meeting abstracts.
  
  
  METHODS
  Randomized trials comparing aspirin to anticoagulants for prevention of VTE following major lower extremity orthopedic surgery.
  
  
  METHODS
  Two reviewers independently extracted data on rates of VTE, bleeding, and mortality.
  
  
  RESULTS
  Of 298 studies screened, 8 trials including 1408 participants met inclusion criteria; all trials screened participants for deep venous thrombosis (DVT). Overall rates of DVT did not differ statistically between aspirin and anticoagulants (relative risk [RR]: 1.15 [95% confidence interval {CI}: 0.68-1.96]). Subgrouped by type of surgery, there was a nonsignificant trend favoring anticoagulation following hip fracture repair but not knee or hip arthroplasty (hip fracture RR: 1.60 [95% CI: 0.80-3.20], 2 trials; arthroplasty RR: 1.00 [95% CI: 0.49-2.05], 5 trials). The risk of bleeding was lower with aspirin than anticoagulants following hip fracture repair (RR: 0.32 [95% CI: 0.13-0.77], 2 trials), with a nonsignificant trend favoring aspirin after arthroplasty (RR: 0.63 [95% CI: 0.33-1.21], 5 trials). Rates of pulmonary embolism were too low to provide reliable estimates.
  
  
  CONCLUSIONS
  Compared with anticoagulation, aspirin may be associated with higher risk of DVT following hip fracture repair, although bleeding rates were substantially lower. Aspirin was similarly effective after lower extremity arthroplasty and may be associated with lower bleeding risk. Journal of Hospital Medicine 2014;9:579-585. © 2014 Society of Hospital Medicine.
authors.affiliation: Geisel School of Medicine at Dartmouth, Pulmonary and Critical Care Medicine, Veterans Affairs Medical Center, White River Junction, Vermont.
authors.forename: Frank S
authors.initials: FS
authors.lastname: Drescher
authors.forename: Brenda E
authors.initials: BE
authors.lastname: Sirovich
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lee
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Morrison
authors.forename: Wesley H
authors.initials: WH
authors.lastname: Chiang
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Larson
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced; D006620:Hip Fractures / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D016032:Randomized Controlled Trials as Topic; D054556:Venous Thromboembolism / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D001241:Aspirin