Long-term Multi-domain Patterns of Change Following Traumatic Brain Injury: A TRACK-TBI LONG Study

Background: Traumatic brain injury (TBI) may be a chronic condition carrying risk for future sequelae; few prospective studies examine long-term post-injury outcomes. We examined prevalence of functional, cognitive, and psychiatric change outcomes from 1–7 years post-injury.

Methods: TRACK-TBI LONG participants were prospectively enrolled within 24-hours of injury and followed to 1-year post-injury; a subset participated in long-term follow-up from 2-7 years post-injury. Reliable change thresholds for the Brief Test of Adult Cognition by Telephone General Composite (cognition) and Brief Symptom Inventory-18 (psychiatric) were derived from orthopedic trauma controls (OTCs). Multiple assessments were completed (post-injury baseline assessment and two or three visits 2-7 years post-injury) within a sample subset. Change was assessed for functional outcome (Glasgow Outcome Scale-Extended[GOSE]) and self/informant report of decline. Prevalence ratios for outcomes classified as stable, improved, declined were reported individually and collectively. Fisher’s-exact test and log-binomial regression models examined factors associated with decline and improvement.

Results: Of the sample (N=1264; mild TBI, GCS 13-15 [mTBI] n=917, moderate-severe TBI GCS 3-12 [msTBI] n=193, or OTC n=154), ‘stable’ was the most prevalent outcome. Functional outcome showed the highest rates of decline, regardless of TBI severity (mild=29%; moderate/severe=23%). When measures were considered collectively, rates of decline included mTBI(21%), msTBI(26%), OTC(15%). Age and pre-injury employment status were associated with functional decline (per 10-years; RR=1.16[95% CI=1.07, 1.25], p<.001; higher in retired/disabled/not working vs. full-time/part-time; RR=1.81[1.33, 2.45], respectively) in the mTBI group. Improvement in functional recovery 2-7 years post-injury was associated with higher BSI scores (per 5 points; RR=1.11[1.04, 1.18], p=.002) and GOSE score of 5-7 (GOSE=8 as reference; RR=2.64[1.75, 3.97], p<.001). Higher BSI scores and identifying as Black (RR=2.28[1.59, 3.25], p<.001) was associated with greater likelihood of improved psychiatric symptoms in mTBI (RR=1.21[1.14, 1.29], p<.001). Greater likelihood of cognitive improvement was observed among those with higher educational attainment in msTBI (per 4-years; RR=2.61[1.43, 4.79], p=.002).

Conclusions and Relevance: Function across domains at 1-year post-injury, a common recovery benchmark, undergo change across the subsequent 6-years. Results support consideration of TBI as a chronic, evolving condition and suggest continued monitoring, rehabilitation, and support is required to optimize long-term independence and quality of life.