Patients with moderate-severe traumatic brain injury may achieve favourable functional outcomes within 12 months of recovery

1. More than half of patients who experienced moderate-severe traumatic brain injury (ms-TBI) achieved favourable functional outcomes after 12 months of recovery, as measured by the Glasgow-Outcome Scale Extended.

2. 71% of patients who presented in a vegetative state following ms-TBI recovered consciousness by 12 months.

Evidence Rating Level: 2 (Good)

Study Rundown: Traumatic Brain Injury (TBI) is a significant driver of morbidity and mortality across the population; survivors may undergo a lengthy and challenging recovery process and long-term prognosis is often uncertain. This prospective cohort study followed a cohort of adult patients who had experienced moderate (Glasgow Coma Scale [GCS] 9-12) or severe (GCS 3-8) TBI. Functional outcome was assessed at 2 weeks, and 3-, 6- and 12 months using the Glasgow-Outcome Scale Extended (GOSE), a validated measure of functional independence across six domains (home, outside home, social, work, relationships, other). 484 patients with ms-TBI were included; 75% had severe TBI and 25% had moderate TBI. The 12-month mortality rate of patients with severe TBI was 30.6%, with most deaths (70%) occurring within the first two-weeks after injury. Of the severe TBI patients surviving to 12 months, 22.9% reported favourable GOSE scores. 41% of the moderate TBI group had a favourable GOSE outcome at just 2-weeks follow up, which increased to 75% at 12 months. Of the 79 patients presenting in a vegetative state following TBI, 71% survived for 12 months, at which point all had regained consciousness. This study demonstrated that even close to a year after injury, clinically significant recovery can be made; most (94%) of these patients had done so within 6 months of injury. After 12 months 19% of severe TBI and 32% of moderate TBI patients reported zero disability via the DRS. The relatively long follow-up period and assessment of cognition as a secondary outcome in particular provide novel information about TBI recovery. The outcome measures selected are relevant to patients and the large sample size may improve the accuracy of prognostication. However, facets of their analysis may risk the influence of confounding factors. One glaring weakness is the study’s lack of accounting for differences in care throughout the course of recovery – for example, patients’ participation in formal rehabilitation programming or access to healthcare were not accounted for. McRea et al. report that their definition of a favourable outcome includes lower GOSE scores than in other studies. It is essential to base prognostic information on commonly-established outcome measures, particularly when communicating about sensitive issues such as functional independence or the withdrawal of life support with patients and their loved ones.

Click to read this study in JAMA Neurology

Relevant Reading: Prognostication in critically-ill patients with severe traumatic brain injury: the TBI-Prognosis multicentre feasibility study

In-Depth [prospective cohort study]: Participants were included from the ongoing TRACK-TBI study, a prospective United States-based database which enrolls patients presenting to hospital and undergoing a computed tomography scan within 24 hours of the injurious event. Outcome measurement and dichotomization of GOSE scores were justified from previous TBI literature. Assessments of GOSE scores were performed both in-person and via telephone visit. Favourable GOSE scores described patients who were at least functionally independent at home, whereas unfavourable scores meant that patients required some degree of daily assisted living. In data analysis, patients who were deceased or in a vegetative state were included in the lowest functional status category. There were no significant differences in interventions following TBI between moderate and severe TBI patients, other than the length of hospitalization (mean 25.9 vs. 15.6 days, p<0.001). Missing data was accounted for by running separate propensity models with each GOSE and DRS score given versus missing. The mean of these analyses concluded that missing data had not significantly affected the results as reported.

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