Rate of incident dementia and care needs among older adults with new traumatic brain injury: a population-based cohort study

Background — The long-term impacts of traumatic brain injury (TBI) in older adults are not well known. Our objective was to describe the association between late-life TBI, incident dementia, and health care needs.

Methods — We conducted a retrospective cohort study using linked health administrative data in Ontario, Canada, and included community-dwelling individuals older than 65 years with a new TBI between Apr. 1, 2004, and Mar. 1, 2020, and up to 17 years of follow-up. People with and without TBI were 1:1 matched on age, sex, and propensity score. We compared rates of incident dementia (≤ 5 yr and > 5 yr), use of publicly funded home care, and admission to a long-term care home, using cause-specific hazard models. We used conditional inference trees to identify subgroups at high risk for outcomes based on associations with individual and intersecting social determinants of health.

Results — We included 132 113 matched pairs. Late-life TBI was associated with an increased rate of incident dementia (≤ 5 yr: hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.66 to 1.72; > 5 yr: HR 1.56,
95% CI 1.53 to 1.59), use of publicly funded home care (HR 1.30, 95% CI 1.29 to 1.31), and admission to a long-term care home (HR 1.45, 95% CI 1.42 to 1.47). Dementia was more common among older females from low-income neighbourhoods than among male peers (29.0% v. 24.7%). Residents of smaller communities received less home care than those in larger communities (60.1% v. 64.6%) and had a higher probability of long-term care home admission (26.3% v. 21.7%).

Interpretation — Late-life TBI in community-dwelling older adults is associated with higher rates of incident dementia, use of publicly funded home care, and admission to a long-term care home, with older females and residents of smaller communities experiencing poorer outcomes. Clinical awareness and policy planning that reflects these needs and population heterogeneity are important.