title: Preoperative anaemia and postoperative outcomes in non-cardiac surgery: a retrospective cohort study.
abstract: BACKGROUND
  Preoperative anaemia is associated with adverse outcomes after cardiac surgery but outcomes after non-cardiac surgery are not well established. We aimed to assess the effect of preoperative anaemia on 30-day postoperative morbidity and mortality in patients undergoing major non-cardiac surgery.
  
  
  METHODS
  We analysed data for patients undergoing major non-cardiac surgery in 2008 from The American College of Surgeons' National Surgical Quality Improvement Program database (a prospective validated outcomes registry from 211 hospitals worldwide in 2008). We obtained anonymised data for 30-day mortality and morbidity (cardiac, respiratory, CNS, urinary tract, wound, sepsis, and venous thromboembolism outcomes), demographics, and preoperative and perioperative risk factors. We used multivariate logistic regression to assess the adjusted and modified (nine predefined risk factor subgroups) effect of anaemia, which was defined as mild (haematocrit concentration >29-<39% in men and >29-<36% in women) or moderate-to-severe (≤29% in men and women) on postoperative outcomes.
  
  
  RESULTS
  We obtained data for 227,425 patients, of whom 69,229 (30·44%) had preoperative anaemia. After adjustment, postoperative mortality at 30 days was higher in patients with anaemia than in those without anaemia (odds ratio [OR] 1·42, 95% CI 1·31-1·54); this difference was consistent in mild anaemia (1·41, 1·30-1·53) and moderate-to-severe anaemia (1·44, 1·29-1·60). Composite postoperative morbidity at 30 days was also higher in patients with anaemia than in those without anaemia (adjusted OR 1·35, 1·30-1·40), again consistent in patients with mild anaemia (1·31, 1·26-1·36) and moderate-to-severe anaemia (1·56, 1·47-1·66). When compared with patients without anaemia or a defined risk factor, patients with anaemia and most risk factors had a higher adjusted OR for 30-day mortality and morbidity than did patients with either anaemia or the risk factor alone.
  
  
  CONCLUSIONS
  Preoperative anaemia, even to a mild degree, is independently associated with an increased risk of 30-day morbidity and mortality in patients undergoing major non-cardiac surgery.
  
  
  BACKGROUND
  Vifor Pharma.
authors: Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors: Khaled M
authors: KM
authors: Musallam
authors: Hani M
authors: HM
authors: Tamim
authors: Toby
authors: T
authors: Richards
authors: Donat R
authors: DR
authors: Spahn
authors: Frits R
authors: FR
authors: Rosendaal
authors: Aida
authors: A
authors: Habbal
authors: Mohammad
authors: M
authors: Khreiss
authors: Fadi S
authors: FS
authors: Dahdaleh
authors: Kaivan
authors: K
authors: Khavandi
authors: Pierre M
authors: PM
authors: Sfeir
authors: Assaad
authors: A
authors: Soweid
authors: Jamal J
authors: JJ
authors: Hoballah
authors: Ali T
authors: AT
authors: Taher
authors: Faek R
authors: FR
authors: Jamali
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood / Q000150:complications*; D015331:Cohort Studies; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000401:mortality; D012307:Risk Factors; D013514:Surgical Procedures, Operative; D055815:Young Adult