Conscious status predicts mortality among patients with isolated traumatic brain injury in administrative data

Abstract

Background: Outcome studies in trauma using administrative data traditionally employ anatomy-based definitions of injury severity; however, physiologic factors, including consciousness, may correlate with outcomes. We examined whether accounting for conscious status in administrative data improved mortality prediction among patients with moderate to severe TBI.

Methods: Patients meeting Centers for Disease Control and Prevention (CDC) guidelines for TBI in the 2006 to 2011 Nationwide Emergency Department Sample were identified. Patients were dichotomized as having no/brief loss of consciousness (LOC) vs extended LOC greater than 1 hour using International Classification of Diseases, Ninth Revision (ICD-9) fifth digit modifiers. Receiver operating curves compared the ability of logistic regression to predict mortality in models that included LOC vs models that did not.

Results: Overall, 98,397 individuals met criteria, of whom 25.8% had extended LOC. In univariate analysis, AIS alone predicted mortality in 69.6% of patients (area under receiver operating characteristic curve .696, 95% CI .689 to .702), extended LOC alone predicted mortality in 76.8% (AUROC .768, 95% CI .764 to .773), and a combination of AIS and extended LOC predicted mortality in 82.6% of cases (AUROC .826, 95% CI .821 to .830). Similar differences were observed in best-fit models.

Conclusions: Accounting for LOC along with anatomical measures of injury severity improves mortality prediction among patients with moderate/severe TBI in administrative datasets. Further work is warranted to determine whether other physiological measures may also improve prediction across a variety of injury types.

Keywords: Administrative databases; Surgical outcomes; TBI; Trauma; Traumatic brain injury.