title: The association between body mass index and clinical outcomes in acute lung injury.
abstract: BACKGROUND
  The association between body mass index (BMI) and outcomes in critically ill patients is unclear. Our objective was to determine the association between BMI and outcomes in a population-based cohort of patients with acute lung injury (ALI).
  
  
  METHODS
  In a prospective cohort study of all ICU patients in King County, Washington, with ALI in 1 year (1999 to 2000), 825 patients had a BMI recorded. Using multivariate analysis, patients in the abnormal BMI groups were compared to normal patients in the following areas: mortality, hospital length of stay (LOS), ICU LOS, duration of mechanical ventilation, and discharge disposition.
  
  
  RESULTS
  There was no mortality difference in any of the abnormal BMI groups compared to normal-weight patients. Severely obese patients had longer hospital LOS than normal-weight patients (mean increase, 10.5 days; 95% confidence interval [CI], 4.8 to 16.2 days; p < 0.001); this was accentuated when analysis was restricted to survivors (mean increase, 14.3 days; 95% CI, 7.1 to 21.6 days; p < 0.001). ICU LOS and duration of mechanical ventilation were also longer in the severely obese group when analysis was restricted to survivors (mean increase, 5.6 days; 95% CI, 1.3 to 9.8 days; p = 0.01; and mean increase, 4.1 days; 95% CI, 0.4 to 7.7 days, respectively; p = 0.03). Severely obese patients were more likely to be discharged to a rehabilitation or skilled nursing facility than to home.
  
  
  CONCLUSIONS
  BMI is not associated with mortality in patients with ALI, but severe obesity is associated with increased morbidity and resource utilization in the hospital and after discharge.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington School of Medicine, Harborview Medical Center, Mailbox 359762, 325 Ninth Ave, Seattle, WA 98104, USA.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Morris
authors.forename: Renee D
authors.initials: RD
authors.lastname: Stapleton
authors.forename: Gordon D
authors.initials: GD
authors.lastname: Rubenfeld
authors.forename: Leonard D
authors.initials: LD
authors.lastname: Hudson
authors.forename: Ellen
authors.initials: E
authors.lastname: Caldwell
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Steinberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015331:Cohort Studies; D003422:Critical Care; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000401:mortality* / Q000628:therapy; D012307:Risk Factors; D016896:Treatment Outcome