The Impact of Age and Severity on Dementia After Traumatic Brain Injury: A Comparison Study

Neurosurgery. 2021 Oct 13;89(5):810-818. doi: 10.1093/neuros/nyab297.

Abstract

Background: Growing evidence associates traumatic brain injury (TBI) with increased risk of dementia, but few studies have evaluated associations in patients younger than 55 yr using non-TBI orthopedic trauma (NTOT) patients as controls to investigate the influence of age and TBI severity, and to identify predictors of dementia after trauma.

Objective: To investigate the relationship between TBI and dementia in an institutional group.

Methods: Retrospective cohort study (2000-2018) of TBI patients aged 45 to 100 yr vs NTOT controls. Primary outcome was dementia after TBI (followed ≤10 yr). Cox proportional hazards models were used to assess risk of dementia; logistic regression models assessed predictors of dementia.

Results: Among 24 846 patients, TBI patients developed dementia (7.5% vs 4.6%) at a younger age (78.6 vs 82.7 yr) and demonstrated higher 10-yr mortality than controls (27% vs 14%; P < .001). Mild TBI patients had higher incidence of dementia (9%) than moderate/severe TBI (5.4%), with lower 10-yr mortality (20% vs 31%; P < .001). Risk of dementia was significant in all mild TBI age groups, even 45 to 54 yr (hazard ratio 4.1, 95% CI 2.7-7.8). A total of 10-yr cumulative incidence was higher in mild TBI (14.4%) than moderate/severe TBI (11.3%) and controls (6.8%) (P < .001). Predictors of dementia include TBI, sex, age, hypertension, hyperlipidemia, stroke, depression, anxiety, and Injury Severity Score.

Conclusion: Mild and moderate/severe TBI patients experienced higher incidence of dementia, even in the youngest group (45-54 yr old), than NTOT controls. All TBI patients, especially middle-aged adults with minor injury who are more likely to be overlooked, should be monitored for dementia.

Keywords: Dementia; Non-TBI orthopedic trauma; TBI; Traumatic brain injury.

MeSH terms

  • Adult
  • Brain Concussion*
  • Brain Injuries, Traumatic* / complications
  • Brain Injuries, Traumatic* / epidemiology
  • Dementia* / epidemiology
  • Dementia* / etiology
  • Humans
  • Injury Severity Score
  • Middle Aged
  • Retrospective Studies