title: Does preoperative anemia adversely affect colon and rectal surgery outcomes?
abstract: BACKGROUND
  Complications associated with blood transfusions have resulted in widespread acceptance of low hematocrit levels in surgical patients. However, preoperative anemia seems to be a risk factor for adverse postoperative outcomes in certain surgical patients. This study investigated the National Surgical Quality Improvement Program (NSQIP) database to determine if preoperative anemia in patients undergoing open and laparoscopic colectomies is an independent predictor for an adverse composite outcome (CO) consisting of myocardial infarction, stroke, progressive renal insufficiency or death within 30 days of operation, or for an increased hospital length of stay (LOS).
  
  
  METHODS
  Hematocrit levels were categorized into 4 classes: severe, moderate, mild, and no anemia. From 2005 to 2008, the NSQIP database recorded 23,348 elective open and laparoscopic colectomies that met inclusion criteria. Analyses using multivariable models, controlling for potential confounders and stratifying on propensity score, were performed.
  
  
  RESULTS
  Compared with nonanemic patients, those with severe, moderate, and mild anemia were more likely to have the adverse CO with odds ratios of 1.83 (95% CI 1.05 to 3.19), 2.19 (95 % CI 1.63 to 2.94), and 1.49 (95% CI 1.20 to 1.86), respectively. Patients with a normal hematocrit had a reduced hospital LOS, compared with those with severe, moderate, and mild anemia (p < 0.01). A history of cardiovascular disease did not significantly influence these findings.
  
  
  CONCLUSIONS
  This large multicenter database analysis suggests that the presence of severe and moderate and even mild preoperative anemia is an independent risk factor for complications and a longer hospital stay after colon surgery.
authors.affiliation: Department of Surgery, Saint Joseph Mercy Health System, Ann Arbor, MI, USA. leichtls@trinity-health.org
authors.forename: Stefan W
authors.initials: SW
authors.lastname: Leichtle
authors.forename: Nicolas J
authors.initials: NJ
authors.lastname: Mouawad
authors.forename: Richard
authors.initials: R
authors.lastname: Lampman
authors.forename: Bonita
authors.initials: B
authors.lastname: Singal
authors.forename: Robert K
authors.initials: RK
authors.lastname: Cleary
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000747:Anemia, Hypochromic / Q000097:blood / Q000150:complications*; D003082:Colectomy / Q000009:adverse effects / Q000379:methods; D015897:Comorbidity; D005260:Female; D006400:Hematocrit; D006801:Humans; D010535:Laparoscopy; D007902:Length of Stay / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood / Q000209:etiology; D016017:Odds Ratio; D059035:Perioperative Period; D011183:Postoperative Complications / Q000097:blood* / Q000209:etiology*; D051437:Renal Insufficiency / Q000097:blood / Q000209:etiology; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000097:blood / Q000209:etiology; D065227:Transfusion Reaction; D016896:Treatment Outcome