title: Increased body mass index and peri-operative risk in patients undergoing non-cardiac surgery.
abstract: BACKGROUND
  Increased BMI is a well known risk factor for morbidity and mortality in hospitalized nonsurgical patients. However, the published evidence for a comparable effect in surgical patients is scarce.
  
  
  METHODS
  This retrospective study was designed to assess the attributable effects of increased BMI (>30 kg/m2) on outcome (hospital mortality, admission to the intensive care unit (ICU), and incidence of intraoperative cardiovascular events (CVE)) in patients undergoing non-cardiac surgery by a computerized anesthesia record-keeping system. The study is based on data-sets of 28065 patients. Cases were defined as patients with BMI >30; controls (BMI 20-25) were automatically selected according to matching variables (ASA physical status, high risk and urgency of surgery, age and sex) in a stepwise fashion. Differences in outcome measures were assessed using univariate analysis. Stepwise regression models were developed to predict the impact of increased BMI on the different outcome measures.
  
  
  RESULTS
  4726 patients (16.8%) were found with BMI >30. Matching was successful for 41.5% of the cases, leading to 1962 cases and controls. The crude mortality rates were 1.1% (cases) vs 1.2% (controls); P =0.50, power=0.88). Admission to ICU was deemed necessary in 6.8% (cases) vs 7.5% (controls), P =0.42, power=0.65, and CVE were detected from the database in 22.3% (cases) vs 21.6% (controls), P =0.30, power=0.60. Using logistic regression analyses, no significant association between higher BMI and outcome measures could be verified.
  
  
  CONCLUSIONS
  Increased BMI alone was not a factor leading to an increased perioperative risk in non-cardiac surgery. This fact may be due to an elevated level of attention while caring for obese patients.
authors.affiliation: Department of Anesthesiology, Intensive Care Medicine, and Pain Management University Hospital Giessen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Klasen
authors.forename: Axel
authors.initials: A
authors.lastname: Junger
authors.forename: Bernd
authors.initials: B
authors.lastname: Hartmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Jost
authors.forename: Matthias
authors.initials: M
authors.lastname: Benson
authors.forename: Tsovinar
authors.initials: T
authors.lastname: Virabjan
authors.forename: Gunter
authors.initials: G
authors.lastname: Hempelmann
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology*; D016022:Case-Control Studies; D003422:Critical Care; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007431:Intraoperative Complications; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000601:surgery*; D012307:Risk Factors