Epilepsy is associated with a 37% increased risk of serious traffic accidents. But taking antiepileptic drugs (AEDs) may not contribute to this risk, according to a new study published online in Neurology.1
The study is the largest so far to evaluate the risk of serious traffic accidents in epilepsy—and the first to evaluate all types of accidents, not just car crashes.
“We cannot determine to what extent the increased risk is seizure-related, but other studies have shown that the majority of car crashes in individuals with epilepsy are not caused by a seizure, although accidents in general seem to be,” wrote first author Helene Sundelin, PhD, of Linköping University Hospital (Linköping, Sweden), and colleagues.
Seizures impair awareness and motor skills, which can interfere with safe driving. While driving restrictions for people with epilepsy vary by country, many require AED treatment as a prerequisite before obtaining a license.
But the issue isn’t so straight forward. AEDs can also impair driving ability. And, people with epilepsy may also suffer from psychiatric disorders and take psychiatric drugs, both of which may affect driving.
To tease out the contribution of these various factors to impaired driving in epilepsy, researchers conducted a study using Swedish national health registers. The study included 29,2220 adults with epilepsy but without cerebral palsy or intellectual disability, matched to 267,637 healthy controls. Researchers followed these individuals from 2006 to 2013 to see how many with epilepsy had serious traffic accidents requiring an ED visit or resulting in death and compared them to controls. Types of accidents included motor vehicular, motorcycle, bicycle, and pedestrian. Researchers also looked at whether the risk for accidents increased with AED use, as well as the impact of psychiatric comorbidities.
Key Results over 7 years for epilepsy vs controls:
• 1.27 times increased risk of serious traffic accidents
o Pedestrian: 2.2 times increased risk
o Bicycle: 1.7 times increased risk
o Motor vehicle: 1.3 increased risk
o Motorcycle: 1.2 times increased risk
• No significantly increased risk of serious traffic accidents with AEDs (HR 0.97; 95% CI 0.85–1.11)
Adjusting for psychiatric disorders and psychotropic medication did not change the results. This suggests that epilepsy is the main reason for increased risk of serious traffic accidents, according to the authors.
Further analysis showed that people with epilepsy have an estimated 297 more serious traffic accidents per year than controls. The numbers of serious pedestrian, bicycle, car and motorcycle accidents per year in epilepsy vs controls were also increased by 32, 133, and 28, respectively.
While AEDs were not linked to serious traffic accidents, only 25% of individuals in this study were actually taking them. These individuals may have been nonadherent, or no longer required AEDs. If they were in remission, they may have been at decreased risk of seizure and impaired driving. This limitation could explain why the study did not find a link between AEDs and serious traffic accidents. Further studies are needed to clarify this point.
The authors drew particular attention to bicycle and pedestrian accidents. Bicyclists are not required to have licenses, yet these accidents can be very serious and even deadly. People with epilepsy could benefit from increased awareness and education about prevention of these types of accidents, they stressed.
“Bicycle accidents in the general population are a growing problem as cycling becomes increasingly popular, which is probably true also for individuals with epilepsy. The increased risk of 70% should have implications both for implementations of safety measures and counseling of individuals with epilepsy. Our results raise the same concern for pedestrians with epilepsy,” they wrote. See: Take Home Points.
1. Sundelin HEK, Chang Z, Larsson H, et al. Epilepsy, antiepileptic drugs, and serious transport accidents: A nationwide cohort study. Neurology. 2018 Feb 28. pii: 10.1212/WNL.0000000000005210.