Background and objectives: Although associated with increased morbidity and mortality, AKI has not been systematically examined in military personnel injured from combat operations in Iraq and Afghanistan.
Design, settings, participants, & measurements: Patients evacuated from Iraq and Afghanistan to a burn unit were examined. AKI was classified by the Acute Kidney Injury Network (AKIN) and Risk-Injury-Failure-Loss-End Stage (RIFLE) schemas. Age, sex, percentage of total body surface area burned (TBSA), percentage of full-thickness burn, inhalation injury, and injury severity score were recorded. Additional data that could be associated with poor outcomes were recorded for patients with TBSA ≥20%. Multivariate logistic regression analyses were performed to determine factors associated with morbidity and mortality.
Results: AKI prevalence rates by the RIFLE and AKIN criteria were 23.8% and 29.9%, respectively. After logistic regression, RIFLE categories of risk (odds ratio [OR], 15.34; 95% confidence interval [CI], 1.75-134; P=0.01), injury (OR, 46.28; 95% CI, 5.02-427; P<0.001), and failure (OR, 126; 95% CI, 13.39->999; P<0.001); AKIN-2 (OR, 23.70; 95% CI, 2.32-242; P=0.008); and AKIN-3 (OR, 130; 95% CI, 13.38->999; P<0.001) were significantly associated with death. AKIN-3, injury, and failure remained significant in the subset of patients with ≥20% TBSA. There was also a strong interaction between TBSA and the stage of AKI with respect to ventilator and intensive care unit days.
Conclusions: AKI is prevalent in military casualties with burn injury and is independently associated with morbidity and mortality after adjustment for factors associated with injury severity.