Prognostic Value of Sequential Organ Failure Assessment (SOFA) Score in Critically-Ill Combat-Injured Patients

Abstract

Background: Infection is a frequent and serious complication after combat-related trauma. The Sequential Organ Failure Assessment (SOFA) score has been shown to have predictive value for outcomes, including sepsis and mortality, among various populations. We evaluated the prognostic ability of SOFA score in a combat-related trauma population. Methods: Combat casualties (2009-2014) admitted to Landstuhl Regional Medical Center (LRMC; Germany) intensive care unit (ICU) within 4 days post-injury followed by transition to ICUs in military hospitals in the United States were included. Multivariate logistic regression was used to determine predictive effect of selected variables and receiver operating characteristic (ROC) curve analysis was used to evaluate overall accuracy of SOFA score for infection prediction. Results: Of the 748 patients who met inclusion criteria, 436 (58%) were diagnosed with an infection (32% bloodstream, 63% skin and soft tissue, and 40% pulmonary) and were predominantly young (median 24 years) males. Penetrating trauma accounted for 95% and 86% of injuries among those with and without infections, respectively (p < 0.001). Median LRMC admission SOFA score was 7 (interquartile range [IQR]: 4-9) in patients with infections versus 4 (IQR: 2-6) in patients without infections (p < 0.001). Thirty-day mortality was 2% in both groups. On multivariate regression, LRMC SOFA score was independently associated with infection development (odds ratio: 1.2; 95% confidence interval: 1.1-1.3). The ROC curve analysis revealed an area under the curve of 0.69 for infection prediction, and 0.80 for mortality prediction. Conclusions: The SOFA scores obtained up to 4 days post-injury predict late onset infection occurrence. This study revealed that for every 1 point increase in LRMC SOFA score, the odds of having an infection increases by a factor of 1.2, controlling for other predictors. The use of SOFA score in admission assessments may assist clinicians with identifying those at higher risk of infection following combat-related trauma.

Keywords: SOFA score; combat trauma; infection; infectious disease; severity score systems; trauma.

Figure 1.

Study Population Flow Diagram. LRMC – Landstuhl Regional Medical Center; ICU – intensive care unit; SOFA – sequential organ failure assessment

Figure 2.

Receiver-Operating Characteristic Curve Analysis of Infection Predictions Using the Admission Sequential Organ Failure Assessment Score. The area under the curve is 0.694 (94% confidence interval: 0.656–0.732; p<0.0001).