Traumatic brain injury and dementia risk: The role of sex, insurance and race

Abstract

AbstractBackgroundAlthough traumatic brain injury (TBI) has been found to be associated with dementia in numerous studies, large‐scale studies of US non‐Veteran populations are scarce. The question of whether sex, insurance, and race influence the risk of dementia after a TBI is not well studied.MethodsWe analyzed data from 97,736 individuals with TBI age 55+ captured in the IBM MarketScan Commercial Claims and Encounter Database and the Medicare Supplemental Database between January 1, 2000 and December 31, 2016. Dementia diagnosis was made from inpatient or outpatient visits during this period with a “wash out” period of one year. The risk of dementia after TBI was established using Cox proportional hazard models adjusted for age, sex, insurance, diabetes, cardiovascular disease, and birth decade. We censored cases at end of enrollment or date of last claim.ResultsOver a median follow‐up of 19.2 (IQR: 6‐42) months, 6417 (5.9%) individuals developed dementia. Older age at injury was associated with a higher risk of dementia in both mild and moderate/severe cases (Age 85+ vs. 55‐64: Mild HR 13.51, 95% CI: 7.97‐22.91; Moderate/Severe HR 6.88, 95% CI: 5.37‐8.83). Women with moderate/severe TBI had a significantly higher hazard of incident dementia compared to men with the same type of injury (HR 1.14, 95% CI: 1.07‐1.21). Individuals with Medicaid and Medicare coverage had a higher risk of dementia than Commercial insurance users independent of TBI severity. The presence of diabetes (Mild: HR 1.46, 95% CI: 1.24‐1.72; Moderate/Severe: 1.28, 95% CI: 1.03‐1.58) and cardiovascular disease (Mild: HR 1.28, 95% CI: 1.03‐1.58; Moderate/Severe: 1.17, 95% CI: 1.07‐1.29) were associated with an increased risk of dementia. A reduction in dementia risk was observed among Blacks (HR 0.85, 95% CI: 0.74‐0.99), and Hispanics/Others (HR 0.63, 95% CI: 0.51‐0.78) in patients covered by Medicaid (N=13304) when compared to non‐Hispanic whites.ConclusionAge at injury, sex and insurance type were associated with increased risk of dementia after a TBI. Blacks and Hispanics/Others covered by Medicaid experienced a lower risk of dementia compared to Whites. Greater efforts to identify factors to mitigate the burden of dementia in large diverse populations are needed.