title: Impact of body mass index on injury in abdominal stab wounds: implications for management.
abstract: BACKGROUND
  Although it is assumed that obese patients are naturally protected against anterior abdominal stab wounds, the relationship has never been formally studied. We sought to examine the impact of body mass index (BMI) on severity of sustained injury, need for operation, and patient outcomes.
  
  
  METHODS
  We conducted a review of all patients presenting with abdominal stab wounds at an urban level I trauma center from January 2000-December 2012. Patients were divided into groups based on their BMI (<18.5, 18.5-29.9, 30-35, and >35). Data abstracted included baseline demographics, physiologic data, and characterization of whether the stab wound had violated the peritoneum, caused intra-abdominal injury, or required an operation that was therapeutic. The one-sided Cochran-Armitage trend test was used for significance testing of the protective effect.
  
  
  RESULTS
  Of 281 patients with abdominal stab wounds, 249 had complete data for evaluation. Chest and abdomen abbreviated injury scale trends decreased with increasing BMI, as did overall injury severity score, the percent of patients severely injured (injury severity score ≥ 25), and length of intensive care unit stay. Rates of peritoneal violation (100%, 84%, 77%, and 74%; P = 0.077), visceral injury (83%, 56%, 50%, and 30%; P = 0.022), and injury requiring a therapeutic operation (67%, 45%, 40%, and 20%; P = 0.034) all decreased with increasing BMI. Patients in the thinnest group required an operation three times more often than those in the most obese.
  
  
  CONCLUSIONS
  Increased BMI protects patients with abdominal stab wounds and is associated with lower incidence of severe injury and need for operation. Heavier patients may be more suitable to observation and serial examinations, whereas very thin patients are more likely to require an operation and be critically injured.
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California. Electronic address: Matthew.Bloom@cshs.org.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Bloom
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Ley
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Douglas Z
authors.initials: DZ
authors.lastname: Liou
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Tri
authors.initials: T
authors.lastname: Tran
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Rex
authors.initials: R
authors.lastname: Chung
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Melo
authors.affiliation: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Margulies
mesh_terms: D000007:Abdominal Injuries / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D009765:Obesity; D016896:Treatment Outcome; D014951:Wounds, Stab / Q000601:surgery*
keywords: Abdominal injury; Body mass index; Obesity; Penetrating injury; Stab; Trauma; Wounds