title: The effect of body mass index on the outcome of critically ill surgical patients.
abstract: BACKGROUND
  The incidence of obesity is rising, and an increasing number of obese patients are admitted to surgical intensive care units (SICUs). However, it is not clear whether obesity is an independent risk factor for increased morbidity and mortality in SICU patients. We examined the effect of obesity on morbidity and mortality in patients admitted to the SICU in this study.
  
  
  METHODS
  We reviewed prospectively acquired SICU data in normal and obese patients with an SICU length of stay >24 hours. Comparability of the groups was assessed using a χ(2) test or Fisher exact test, as appropriate, for categorical variables and analysis of variance (ANOVA) or the Kruskal-Wallis test, as appropriate, for continuous variables.
  
  
  RESULTS
  Of the 1792 consecutive patients evaluated, 711 had a normal body mass index (BMI), and 993 were either preobese or obese. There was no statistically significant difference across the 5 BMI groups with respect to any of the 3 comorbidity indices (Acute Physiology and Chronic Health Evaluation III [APACHE III], Simplified Acute Physiology Score, or Multiple Organ Dysfunction Score). There was no statistically significant difference in the intensive care unit (ICU) length of stay and hospital length of stay or time-to-ICU mortality (log-rank test P = .054) among the 5 BMI groups. A Cox regression analysis and backward elimination algorithm selected APACHE III to be the most important explanatory variable for survival time.
  
  
  CONCLUSIONS
  Obesity does not affect the mortality of patients admitted to the SICU. We conclude that obesity cannot be used as an independent predictive mortality outcome variable in patients admitted to the SICU.
authors.affiliation: Department of Surgery and Critical Care, Long Island Jewish Medical Center, New Hyde Park, New York 11004, USA. drrgupta@hotmail.com
authors.forename: Rajeev
authors.initials: R
authors.lastname: Gupta
authors.forename: Manuel
authors.initials: M
authors.lastname: Villa
authors.forename: Emanuel
authors.initials: E
authors.lastname: Agaba
authors.forename: Garry
authors.initials: G
authors.lastname: Ritter
authors.forename: Cristina
authors.initials: C
authors.lastname: Sison
authors.forename: Corrado P
authors.initials: CP
authors.lastname: Marini
authors.forename: Rafael
authors.initials: R
authors.lastname: Barrera
mesh_terms: D018806:APACHE; D000368:Aged; D015992:Body Mass Index; D016638:Critical Illness / Q000453:epidemiology / Q000628:therapy; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D009017:Morbidity; D009518:New York; D009765:Obesity / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013514:Surgical Procedures, Operative; D016896:Treatment Outcome