Outcomes after Traumatic Brain Injury with and Without Computed Tomography

Our recent improved understanding of traumatic brain injury (TBI) comes largely from cohort studies of TBI patients with indication for computed tomography (CT). Using CT head as an inclusion criterion may overestimate poor outcomes after TBI with Glasgow Coma Scale (GCS) 13-15. We aimed to compare outcomes after TBI in adults who had a head CT scan (with negative findings) versus those who had no CT when presenting to an emergency department. This was a secondary analysis of a trial that recruited adults with GCS = 13-15 after TBI in Vancouver, Canada. We included 493 participants (18-69 years, 54% female), after removing n = 19 with traumatic abnormalities on CT (intracranial and/or skull fracture). Outcomes were Glasgow Outcome Scale Extended (GOSE), Rivermead Post-Concussion Symptoms Questionnaire (RPQ), Patient Health Questionnaire (PHQ)-9, and generalized anxiety disorder (GAD)-7 at 6 months post-injury. Over half (55%) of participants received a CT. At 6 months, 55% of participants with CT and 49% without CT had functional limitations on GOSE; 32% with CT and 33% without CT reported severe post-concussion symptoms (RPQ ≥16); 26% (with CT) and 28% (without CT) screened positive for depression (PHQ-9 ≥ 10), and 25% (with CT) and 28% (without CT) screened positive for anxiety (GAD-7 ≥ 8). In regression adjusted for personal variables, participants with CT had somewhat higher odds of worse functioning (ordinal GOSE; 1.4, 95% CI 1.0-2.0) but similar odds of severe post-concussion symptoms (1.1, 95% CI: 0.7-1.7), and depression (1.1, 95% CI: 0.7-1.7) and anxiety (1.0, 95% CI: 0.6-1.5) symptoms. Adults with and without head CT have mostly comparable outcomes from TBI with GCS = 13-15. Requiring CT by clinical indication for study entry may not create problematic selection bias for outcome research.