title: Rhabdomyolysis among critically ill combat casualties: Associations with acute kidney injury and mortality.
abstract: BACKGROUND
  Rhabdomyolysis has been associated with poor outcomes in patients with traumatic injury, especially in the setting of acute kidney injury (AKI). However, rhabdomyolysis has not been systematically examined in a large cohort of combat casualties injured in the wars in Iraq and Afghanistan.
  
  
  METHODS
  We conducted a retrospective study of casualties injured during combat operations in Iraq and Afghanistan who were initially admitted to the intensive care unit from February 1, 2002, to February 1, 2011. Information on age, sex, Abbreviated Injury Scale (AIS) score, Injury Severity Score (ISS), mechanism of injury, shock index, creatine kinase, and serum creatinine were collected. These variables were examined via multivariate logistic and Cox regression analyses to determine factors independently associated with rhabdomyolysis, AKI, and death.
  
  
  RESULTS
  Of 6,011 admissions identified, a total of 2,109 patients met inclusion criteria and were included for analysis. Rhabdomyolysis, defined as creatine kinase greater than 5,000 U/L, was present in 656 subjects (31.1%). Risk factors for rhabdomyolysis identified on multivariable analysis included injuries to the abdomen and extremities, increased ISS, male sex, explosive mechanism of injury, and shock index greater than 0.9. After adjustment, patients with rhabdomyolysis had a greater than twofold increase in the odds of AKI. In the analysis for mortality, rhabdomyolysis was significantly associated with death until AKI was added, at which point it lost statistical significance.
  
  
  CONCLUSIONS
  We found that rhabdomyolysis is associated with the development of AKI in combat casualties. While rhabdomyolysis was strongly associated with mortality on the univariate model and in conjunction with both ISS and age, it was not associated with mortality after the inclusion of AKI. This suggests that the effect of rhabdomyolysis on mortality may be mediated by AKI.
  
  
  METHODS
  Prognostic and epidemiologic study, level III.
authors.affiliation: From the David Grant Medical Center (I.J.S., T.I.F.), Fairfield, California; Uniformed Services University of the Health Sciences (I.J.S., J.A.S., J.E., D.H.Z., K.K.C.), Bethesda, Maryland; and US Air Force Center for Sustainment of Trauma and Readiness Skills (R.F.), Baltimore, Maryland; San Antonio Military Medical Center (J.A.S., M.S.C.); 59th Medical Wing, Wilford Hall Ambulatory Surgical Center (J.D.R.); and United States Army Institute of Surgical Research (J.T.H., K.K.C.), San Antonio, Texas; University of Cincinnati Medical Center (J.E.), Cincinnati, Ohio; Oregon Health & Science University (D.H.Z.), Portland, Oregon.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Stewart
authors.forename: Tarra I
authors.initials: TI
authors.lastname: Faulk
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Sosnov
authors.forename: Michael S
authors.initials: MS
authors.lastname: Clemens
authors.forename: Joel
authors.initials: J
authors.lastname: Elterman
authors.forename: James D
authors.initials: JD
authors.lastname: Ross
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Howard
authors.forename: Raymond
authors.initials: R
authors.lastname: Fang
authors.forename: David H
authors.initials: DH
authors.lastname: Zonies
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Chung
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology* / Q000401:mortality; D000328:Adult; D055826:Afghan Campaign 2001-; D002423:Cause of Death / Q000639:trends; D003402:Creatine Kinase / Q000097:blood; D016638:Critical Illness / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D054527:Mass Casualty Incidents; D008889:Military Personnel; D009104:Multiple Trauma; D011379:Prognosis; D012189:Retrospective Studies; D012206:Rhabdomyolysis / Q000150:complications* / Q000401:mortality; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D015599:Trauma Severity Indices; D014481:United States / Q000453:epidemiology; D014947:Wounds and Injuries / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D055815:Young Adult
chemical_list: D003402:Creatine Kinase