Rhabdomyolysis among Critically Ill Combat Casualties: Long-Term Outcomes.

BACKGROUND: Although rhabdomyolysis has been associated with acute kidney injury and mortality in the short term, the long-term consequences of an episode of rhabdomyolysis remain unknown. We sought to identify the long-term outcomes of rhabdomyolysis, including mortality, renal function, and incidence of hypertension (HTN), among service members initially admitted to the intensive care unit after sustaining a combat injury in Iraq or Afghanistan between February 1, 2002 and February 1, 2011. METHODS: Information on age, sex, injury severity score, mechanism of injury, serum creatinine, burn injury, presenting mean arterial pressure, and creatine kinase were retrospectively collected and analyzed for 2,208 patients. Standard descriptive tests were used to compare characteristics of patients with and without rhabdomyolysis. Competing risk Cox proportional hazards models were performed to assess the associated risk of rhabdomyolysis with both HTN and poor renal function. RESULTS: While rhabdomyolysis was associated with HTN on univariate analysis (hazard ratio [HR] 1.30, 95% CI 1.03-1.64; p = 0.029), this difference did not persist on multivariable analysis (HR 1.27, 95% CI 0.99-1.62; p = 0.058). The median estimated glomerular filtration rate (eGFR) was 119 (interquartile range [IQR] 103-128) among those with rhabdomyolysis, compared with 108 (IQR 94-121) in the group without rhabdomyolysis (p < 0.001). CONCLUSION: After adjustment, patients with rhabdomyolysis were not at an increased risk of HTN compared to patients without rhabdomyolysis. eGFR was paradoxically higher in patients with rhabdomyolysis. There was no association found between rhabdomyolysis and mortality.

Rhabdomyolysis among critically ill combat casualties: Associations with acute kidney injury and mortality.

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. CONCLUSION: 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. LEVEL OF EVIDENCE: Prognostic and epidemiologic study, level III.