Abstract 024: Traumatic Brain Injury And Long-term Risk Of Stroke Among U.S. Military Veterans

Abstract

Background: Traumatic brain injury (TBI) results in cerebrovascular injury and has been associated with shorter-term (i.e., <4 years) risk of stroke. Longer-term associations of TBI with stroke and transient ischemic attack (TIA) remain less clear. Objective: To examine the association between TBI and long-term risk of stroke/TIA among U.S. military veterans. Methods: We used data from 613,592 U.S. military veterans without stroke at baseline (306,796 with TBI matched 1:1 on age, sex, race, and TBI index date to 306,796 without TBI) who were included in the Veterans Health Administration inpatient and outpatient database (National Patient Care Database) from 10/1/2002 to 9/30/2019. TBI and stroke/TIA were defined using International Classification of Diseases, Ninth and Tenth Revisions (ICD-9/10) codes. We conducted Cox proportional hazards models with an origin of 30-days after the index date in order to exclude stroke/TIA events occurring within 30-days of TBI. Models were adjusted for demographics and medical and psychiatric comorbidities. Formal testing for interaction by age, sex, and race was performed. Results: Overall, included veterans were an average age of 50 years, 9% were female, and 75% were of White race. Over a median of 5 years of follow-up, 36,351 stroke/TIA events (23,241 among veterans with TBI and 13,290 among veterans without TBI) occurred. Veterans with TBI had 1.73 times (95% CI 1.69-1.77) increased risk of any stroke or TIA compared to veterans without TBI. The risk was stronger for hemorrhagic stroke compared to ischemic stroke and compared to TIA (Table). Associations of TBI with risk of any stroke or TIA were stronger among older (aged ≥65 years; HR 2.09, 95% CI 2.02-2.17) compared to younger veterans and were less strong among Blacks (HR 1.48, 95% CI 1.41-1.55) compared to other races (p-interaction for both <0.001). Conclusion: Among U.S. military veterans, TBI was associated with increased long-term risk of stroke/TIA. Future work focused on stroke prevention in TBI populations is warranted.