Acute Kidney Injury in Critically Injured Combat Veterans: A Retrospective Cohort Study.

Background: Acute kidney injury (AKI) has been associated with mortality after traumatic injury. However, there is a paucity of data for military service members with injuries received in combat. We sought to identify risk factors for AKI after combat trauma and evaluate whether AKI is a predictor of mortality.

Study Design: Retrospective observational study.

Settings & Participants: US service members who were critically wounded in Iraq or Afghanistan from February 1, 2002, to February 1, 2011, and survived until evacuation to Landstuhl Regional Medical Center, Germany.

Predictors: Demographic variables, vital signs, injury severity score, presence of burn injury, and mechanism of injury as defined at the time of initial injury, as well as the presence of AKI ascertained within the first 7 days using KDIGO (Kidney Disease: Improving Global Outcomes) serum creatinine criteria.

Outcomes: Logistic regression models were used to identify risk factors for both AKI and death.

Results: Of 6,011 records, 3,807 were included for analysis after excluding patients with missing data. AKI occurred in 474 (12.5%) patients and 112 (2.9%) died. More patients with versus without AKI died (n=62 [13.1%] vs n=50 [1.5%]; P<0.001). After adjustment, AKI was a predictor of mortality (OR, 5.14; 95% CI, 3.33-7.93; P<0.001). Predictors of AKI were age, African American race, injury severity score, amputations, burns, and presenting vital signs.

Limitations: AKI diagnoses limited to creatinine-based definitions.

Conclusions: AKI predicted mortality in combat veterans injured in the wars in Iraq and Afghanistan.