The likelihood of developing post-traumatic epilepsy (PTE) rises with the severity of traumatic brain injury, according to a nationwide study from Sweden. The greatest risk increase was seen with fall injuries, Dr. Johan Zelano of the University of Gothenburg and his colleagues report in the Journal of Neurology, Neurosurgery, and Psychiatry. "From a societal perspective," they write, "prevention of fall seems to be at least as important as reducing violence and traffic accidents in order to reduce the burden of PTE." Earlier studies show traumatic brain injury (TBI) is a major cause of epilepsy. To help determine the risk after various kinds of brain trauma and identify risk factors, the researchers analyzed data on all adults hospitalized for brain trauma in Sweden between 2000 and 2010. They identified nearly 112,000 patients with a first TBI hospitalization and no prior epilepsy and three times as many age- and sex-matched controls; patients who died within 30 days of sustaining TBI were excluded. The median age in both groups was 56, and 59% were men. Using Kaplan-Meier survival analysis, the team estimated the 10-year risk of epilepsy at 4.0% (95% confidence interval, 3.8% to 4.2%) among the trauma patients and 0.9% (95% CI, 0.9% to 0.9%) in the control group. The Cox proportional hazard ratio of epilepsy for any TBI was 3.9 compared with control (95% CI, 3.7 to 4.1) after adjusting for age, sex and central-nervous-system comorbidities. When the TBI patients were stratified by the type and severity of their injury, the risk was highest following focal cerebral injury (12.0%), followed by diffuse cerebral injury (7.3%), extracerebral injury (5.9%), fracture (3.0%) and mild injury (2.6%). Consistent with past studies, the TBI severity was the major determinant of epilepsy risk, mirroring findings for stroke. Dr. Zelano said the results were unchanged in sensitivity analyses. He cautioned, however, that the impact of alcohol use on PTE risk was not addressed and could be a significant confounder. "It is probably missed a lot," Dr. Zelano told Reuters Health by email, because the logging of information about patient alcohol use tends to be both arbitrary and inconsistent. A study that properly accounted for excessive alcohol use, he said, "would have to rely on prospectively collected data." By injury mechanism, the risk was most increased after falls, with a hazard ratio of 4.5, followed by transportation accidents (HR, 1.7) and violence (1.3). Dr. David Thurman, a retired neurologist and epidemiologist with a 20-year career at the Centers for Disease Control and Prevention in Atlanta, praised the study, noting that, "as far as administrative hospital-coded records go, I think the Scandinavian countries are among the best, if not the best." He told Reuters Health by phone that the analysis offers "useful" confirmation of previous work, including his own team's 2018 study, which relied on data from insurance claims. But he also pointed out some limitations. "We're not looking at the very mildest of traumatic brain injuries," Dr. Thurman said of the Swedish study, such as "the young athlete who gets his bell rung playing football, but is able to stand up after a minute, walk off the field and doesn't go to the hospital." "We haven't answered whether repeated mild concussions might increase one's risk for epilepsy," he said. "That's something that should be looked at more closely." —Matthew Phelan Source
