title: Body adipose content is independently associated with a higher risk of organ failure and nosocomial infection in the nonobese patient postinjury.
abstract: OBJECTIVE
  Obesity defined by a body mass index (BMI) >30 kg/m is associated with increased morbidity and mortality following trauma. Evidence suggests that obesity represents a state of chronic inflammation and that the adipose tissue content may affect the intensity and resolution of inflammatory response. We sought to avoid the confounding effects attributable to obesity and determine the association of BMI and outcomes following injury in nonobese patients.
  
  
  METHODS
  Data were obtained from a multicenter prospective cohort study evaluating outcomes in blunt-injured adults with hemorrhagic shock. Only patients with a BMI≥18.5 and<30 were analyzed. Those with isolated traumatic brain injury and cervical cord injury and those who survived<24 hours were excluded. Logistic regression was used to evaluate the effects of BMI on mortality, multiple organ failure (MOF, multiple organs dysfunction score [MODS]>5), and nosocomial infection (NI) after adjusting for differences in demographics, injury severity, early resuscitation needs, shock parameters, and comorbidities.
  
  
  RESULTS
  Overall mortality, MOF, and NI rates for the study cohort (n=820) were 13%, 37%, and 46%, respectively. Median Injury Severity Score was 33 (interquartile range, 22-41). Median BMI for the study cohort was 25 (interquartile range, 23-27). As BMI increased, maximum organ dysfunction scores also significantly increased for cardiac, respiratory, and renal systems. Logistic regression revealed no significant association with mortality (odds ratio [OR]=0.95; 95% confidence interval [CI], 0.9-1.0); however, BMI was independently associated with a higher risk of MOF (OR=1.09; 95% CI, 1.02-1.06) and NI (OR=1.07; 95% CI, 1.01-1.13). For every single-point increase in BMI, the risk of MOF and NI increase by 9% and 7%, respectively.
  
  
  CONCLUSIONS
  The risk of MOF and NI increases as BMI increases in the nonobese injured patient. These results suggest that body adipose content may be associated with the magnitude of or extent of the inflammatory response postinjury. Further studies are needed to elucidate the mechanism responsible for this association.
authors.affiliation: Division of General Surgery and Trauma, Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Edmonds
authors.forename: Joseph
authors.initials: J
authors.lastname: Cuschieri
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Minei
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Rosengart
authors.forename: Ronald V
authors.initials: RV
authors.lastname: Maier
authors.forename: Brian G
authors.initials: BG
authors.lastname: Harbrecht
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Billiar
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Peitzman
authors.forename: Ernest E
authors.initials: EE
authors.lastname: Moore
authors.forename: Jason L
authors.initials: JL
authors.lastname: Sperry
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology / Q000503:physiopathology; D000328:Adult; D015992:Body Mass Index; D016001:Confidence Intervals; D003428:Cross Infection / Q000209:etiology*; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D016015:Logistic Models; D008297:Male; D009102:Multiple Organ Failure / Q000209:etiology*; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D014947:Wounds and Injuries / Q000150:complications* / Q000401:mortality