title: Risk factors for bleeding in major abdominal surgery using heparin thromboprophylaxis.
abstract: BACKGROUND
  Patients undergoing major abdominal surgery are at risk of both bleeding and thrombotic complications and usually receive heparin thromboprophylaxis.
  
  
  METHODS
  Risk factors for perioperative bleeding were examined in 3,809 patients in a double-blind, randomized trial investigating heparin thromboprophylaxis. The risk factors were modeled by logistic regression, and a risk score was calculated using the significant factors in the model.
  
  
  RESULTS
  Bleeding was associated with the following factors in the model, given as adjusted odds ratios (ORa [95% confidence interval]): male sex (ORa 1.68 [1.21 to 2.34] P = 0.003), malignancy (ORa 1.69 [1.21 to 2.34] P = 0.008), gynecological surgery (ORa 1.62 [1.12 to 2.35] P = 0.011), and complex surgery (ORa 2.7 [2.02 to 3.62] P < 0.001). The risk of excessive bleeding for 0, 1, 2, and 3 risk factors was 2%, 6%, 11%, and 21%, respectively.
  
  
  CONCLUSIONS
  The recognition of patients with these risk factors associated with perioperative bleeding should result in increased vigilance and may lead to modification of surgical and medical therapy.
authors.affiliation: Department of Medicine, King's College School of Medicine and Dentistry, London, United Kingdom.
authors.forename: A T
authors.initials: AT
authors.lastname: Cohen
authors.forename: M B
authors.initials: MB
authors.lastname: Wagner
authors.forename: M S
authors.initials: MS
authors.lastname: Mohamed
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016063:Blood Loss, Surgical; D004311:Double-Blind Method; D005260:Female; D005836:Genitalia, Female / Q000601:surgery; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D016017:Odds Ratio; D012307:Risk Factors; D012737:Sex Factors; D013923:Thromboembolism / Q000517:prevention & control*
chemical_list: D006493:Heparin