People who survive a traumatic brain injury are three times more likely to die prematurely than are those who have not, according to results from a large population-based study.
The study, which drew from more than 4 decades of data from Swedish national patient registries and death records, also found that nearly half of the TBI patients who died prematurely died from suicide, violence, or injuries.
For their research, published online Jan. 15 (JAMA Psychiatry 2014 [doi:10.1001/jamapsychiatry.2013.3935]), investigators, led by Dr. Seena Fazel of Oxford (England) University, evaluated data from 218,300 men and women who had survived for 6 months or more after TBI with age and sex-matched controls (n = 2,163,190).
Of all the TBI patients, 69.3% were men, 80.5% were not married, and 9.3% had preexisting psychiatric disorders, including 4.4% with substance abuse diagnoses.
Dr. Fazel and his colleagues found that the TBI patients saw a threefold higher mortality before age 56 years, compared with controls, even after researchers adjusted for socioeconomic confounders (adjusted odds ratio, 3.2; 95% confidence interval, 3.0-3.4). Of those who died early, the median age was 18.6 years at the time of the TBI and 40.6 years at death.
Dr. Robert Robinson
The study also looked at unaffected siblings of the TBI patients (n = 150,513) and found significantly greater odds of premature death in the TBI group, compared with their siblings (OR, 2.6; 95% CI, 2.3-2.8). Still, the difference was less than that seen with the general population controls, suggesting that some genetic and environmental factors might be partly responsible for the higher mortality.
The rate of premature deaths among the TBI survivors was low overall, but it was higher among those with psychiatric or substance abuse diagnoses. Mortality from suicide, injuries, and assault was significantly higher in the TBI group than the control group, accounting for 48.6% of premature deaths among TBI patients.
Dr. Fazel and his colleagues wrote in their analysis that in light of these findings, clinical guidelines might need to be revised to focus on preventing mortality beyond the first few months after injury and address high rates of psychiatric comorbidity and substance abuse among TBI patients.
In an editorial accompanying Dr. Fazel and his colleagues’ article, Dr. Robert G. Robinson of the department of psychiatry administration at the University of Iowa in Iowa City, proposed that some of the excess mortality seen among the TBI patients might be attributable to personality – something the study authors also acknowledged as a potential confounder (JAMA Psychiatry 2014 Jan. 15 [doi:10.1001/jamapsychiatry.2013.4241]).
"The preponderance of premature deaths due to external factors suggests that one of the most likely explanations for the findings in the current study is the existence of personality characteristics of impulsiveness, risk-taking behaviors, and proneness to substance abuse. These patients incur a TBI and continue to demonstrate these behaviors after the TBI, which ultimately leads to a fatality," Dr. Robinson wrote.
Dr. Robinson, echoing the recommendations of Dr. Fazel and his colleagues, argued that recognizing such patients is important "because half of these deaths are due to preventable behaviors." Some prevention strategies, he wrote, might include screening TBI patients at discharge for personality characteristics and treating those with the most impulsive risk-taking traits, or administering antidepressants to those seen as vulnerable to depression.
The study authors and Dr. Robinson noted among the study’s strengths of its very large sample size, making it the largest of its kind to date, its long follow-up, and its use of sibling controls. One weakness noted by Dr. Robinson was that the cause of the TBI could not be specified in most cases and that the severity of TBI could only be quantified in some cases by duration of hospitalization.
Because pathologic features, symptoms, and the course of TBI can differ depending on the cause or severity of the injury, Dr. Robinson wrote, "further studies in this area should focus on whether the cause of brain injury, type of brain injury, severity of injury, or premorbid personality characteristics are associated with the highest risk of premature deaths."
Dr. Fazel and his colleagues’ study was funded by grants from the Wellcome Trust, the Swedish Prison and Probation Service, and the Swedish Research Council. None of its authors declared conflicts of interest. Dr. Robinson disclosed no conflicts of interest related to his editorial.