title: Extreme obesity and outcomes in critically ill patients.
abstract: BACKGROUND
  Recent literature suggests that obese critically ill patients do not have worse outcomes than patients who are normal weight. However, outcomes in extreme obesity (BMI ≥ 40 kg/m(2)) are unclear. We sought to determine the association between extreme obesity and ICU outcomes.
  
  
  METHODS
  We analyzed data from a multicenter international observational study of ICU nutrition practices that occurred in 355 ICUs in 33 countries from 2007 to 2009. Included patients were mechanically ventilated adults ≥ 18 years old who remained in the ICU for > 72 h. Using generalized estimating equations and Cox proportional hazard modeling with clustering by ICU and adjusting for potential confounders, we compared extremely obese to normal-weight patients in terms of duration of mechanical ventilation (DMV), ICU length of stay (LOS), hospital LOS, and 60-day mortality.
  
  
  RESULTS
  Of the 8,813 patients included in this analysis, 3,490 were normal weight (BMI 18.5-24.9 kg/m(2)), 348 had BMI 40 to 49.9 kg/m(2), 118 had BMI 50 to 59.9 kg/m(2), and 58 had BMI ≥ 60 kg/m(2). Unadjusted analyses suggested that extremely obese critically ill patients have improved mortality (OR for death, 0.77; 95% CI, 0.62-0.94), but this association was not significant after adjustment for confounders. However, an adjusted analysis of survivors found that extremely obese patients have a longer DMV and ICU LOS, with the most obese patients (BMI ≥ 60 kg/m(2)) also having longer hospital LOS.
  
  
  CONCLUSIONS
  During critical illness, extreme obesity is not associated with a worse survival advantage compared with normal weight. However, among survivors, BMI ≥ 40 kg/m(2) is associated with longer time on mechanical ventilation and in the ICU. These results may have prognostic implications for extremely obese critically ill patients.
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Vermont, Burlington, VT.
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Martino
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Vermont, Burlington, VT. Electronic address: renee.stapleton@uvm.edu.
authors.forename: Renee D
authors.initials: RD
authors.lastname: Stapleton
authors.affiliation: Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada.
authors.forename: Miao
authors.initials: M
authors.lastname: Wang
authors.affiliation: Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada; Department of Community Health and Epidemiology, Queen's University, Kingston, ON, Canada.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Day
authors.affiliation: Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada; Department of Community Health and Epidemiology, Queen's University, Kingston, ON, Canada.
authors.forename: Naomi E
authors.initials: NE
authors.lastname: Cahill
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Vermont, Burlington, VT.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Dixon
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Vermont, Burlington, VT.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Suratt
authors.affiliation: Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada; Department of Community Health and Epidemiology, Queen's University, Kingston, ON, Canada; Department of Medicine, Queen's University, Kingston, ON, Canada.
authors.forename: Daren K
authors.initials: DK
authors.lastname: Heyland
mesh_terms: D018806:APACHE; D016009:Chi-Square Distribution; D016638:Critical Illness / Q000401:mortality*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000401:mortality*; D016016:Proportional Hazards Models; D012121:Respiration, Artificial; D012307:Risk Factors; D013997:Time Factors