Comparing Acute and 1-Year Outcomes Between Fall- and Motor Vehicle-Related Traumatic Brain Injury: A NIDILRR TBI...

Traumatic brain injury (TBI) mechanisms are often grouped together in research. Differences in acute and long-term outcomes across mechanisms of injury (MOIs) remain unclear, partly because of confounding by age. Modeling MOI-specific effects can inform clinical triage and prognostication. We examined the relationship between motor vehicle accidents (MVAs) vs falls, the 2 most common MOIs, and acute and 1-year post-injury outcomes, after rigorous control of demographic and preinjury personal factors.

Data were analyzed from individuals with moderate-to-severe TBI requiring inpatient rehabilitation from the TBI Model Systems National Database, a multicenter prospective longitudinal cohort study. The analytic sample was restricted to individuals aged 16-79 years with an MOI due to MVA or fall occurring between April 2010 and January 2023. We used inverse probability of treatment weighting, based on propensity scores, to adjust for 14 demographic and preinjury personal characteristics and estimate the causal effect of MOI on acute and 1-year outcomes after TBI. Acute hospital and rehabilitation outcomes included the following: Glasgow Coma Scale (GCS), sedation, intubation, post-traumatic amnesia duration, time to follow commands (TFC), length of hospital stay (LOS), and Functional Independence Measure (FIM) cognitive and motor scores. One-year outcomes included the following: Disability Rating Scale and Participation Assessment with Recombined Tools Objective.

Among 5,181 participants (mean age 45.1 ± 19.5, 70% male), 48.4% sustained their injury from MVAs and 51.6% from falls. After weighting and multiple comparisons adjustment, the MVA group had lower GCS total scores by 1.27 points (95% CI -1.92 to -0.61; adjusted p = 0.001), greater odds of receiving sedation (odds ratio 1.43, 95% CI 1.11-1.85; adjusted p = 0.014), longer TFC by 1.64 days (95% CI 0.39-2.89; adjusted p = 0.017), and lower discharge FIM motor scores by 4.28 points (95% CI -7.50 to -1.26; adjusted p = 0.014). At 1 year after injury, disability levels and community participation did not differ.

MVA-related TBI was associated with worse acute outcomes. However, by 1 year after injury, disability level and community participation do not differ. This work highlights novel findings in short-term and long-term outcomes after falls and MVAs, the leading TBI causes, which are not explained by confounders such as age. Findings may not generalize beyond patients receiving inpatient rehabilitation for TBI.