Barnes DE, et al. - Researchers studied the link between traumatic brain injury (TBI) severity, loss of consciousness (LOC) and dementia diagnosis in veterans. It was concluded that even mild TBI without LOC appeared to be related to more than a 2-fold increase in the risk of dementia diagnosis among more than 350,000 veterans.

Methods

• The enrollment consisted of all patients diagnosed with a TBI in the Veterans Health Administration health care system from October 1, 2001, to September 30, 2014, and a propensity-matched comparison group.
• Exclusion criteria included patients with dementia at baseline.
• TBIs were determined via the Comprehensive TBI Evaluation database, which was restricted to Iraq and Afghanistan veterans, and the National Patient Care Database, comprising of veterans of all eras.
• During this trial, the severity of each TBI was based on the most severe injury recorded and classified as mild without LOC, mild with LOC, mild with LOC status unknown, or moderate or severe using Department of Defense or Defense and Veterans Brain Injury Center criteria.
• International Classification of Diseases, Ninth Revision codes aided in determining the dementia diagnoses during follow-up and medical and psychiatric comorbidities in the 2 years prior to the index date.
• Dementia diagnosis in veterans who had experienced TBI with or without LOC and control participants without TBI exposure served as the primary outcome.

Results

• A total of 178,779 patients diagnosed with a TBI in the Veterans Health Administration health care system and 178,779 patients in a propensity-matched comparison group were recruited.
• Mean (SD) age of veterans was nearly 49.5 (18.2) years at baseline; 33,250 (9.3%) were women, and 259,136 (72.5%) were non-Hispanic white individuals.
• Minor variations were reported between veterans with and without TBI.
• The development of dementia was seen in 4,698 veterans (2.6%) without TBI compared with 10,835 (6.1%) of those with TBI.
• Following adjustment for demographics and medical and psychiatric comorbidities, adjusted hazard ratios for dementia were calculated to be 2.36 (95% CI, 2.10-2.66) for mild TBI without LOC, 2.51 (95% CI, 2.29-2.76) for mild TBI with LOC, 3.19 (95% CI, 3.05-3.33) for mild TBI with LOC status unknown, and 3.77 (95% CI, 3.63-3.91) for moderate to severe TBI.