Traumatic Brain Injury Poses Long-Term Issues for Insurers

Natasha Richardson, a 45-year-old actress, recently died from an epidural hematoma that developed after she struck her head in a fall during a private ski lesson at Mount Tremblant. Her death was likely preventable. She refused transport to a local hospital in the ambulance summoned by the ski patrol and instead returned to her hotel. By the time that she decided to accept care, she was outside the “golden hour” that is critical to survival from traumatic brain injuries (TBI) and could not be saved. Her death was unnecessary and an uncommon outcome.

Increased Survival, Increased Long-Term Risk
The survival rate for TBI patients has dramatically increased in recent years. TBI survivors often request compensation not merely for the acute injuries and chronic impairments they are actually manifesting, but also for their risk of developing additional disorders in the future, a concept commonly referred to as epidemiological risk.

Epidemiological risk: The likelihood that a population will develop a specific disorder and the distribution and determinants of the disorder in that population.

Epilepsy commonly results from trauma to the skull and brain. A study published this year in the journal Epilepsia concluded that seizures occur in about 15%–20% of patients with severe brain trauma. About 5% of the chronic cases of seizure disorder in the general population are attributable to a prior TBI. Penetrating brain injury results in a risk of post-traumatic epilepsy of approximately 50%; whereas, non-penetrating head injury with focal contusions and intracranial hemorrhages increases the risk to approximately 30%.

The First Reference Study of Epilepsy Risk After TBI
A forthcoming article in the journal Lancet is considered the first “reference study” for determining the epidemiological risk of a TBI claimant developing post-traumatic epilepsy. The population-based study consisted of 1,605,216 people born in Denmark—78,500 experienced at least one head injury, and more than 17,400 had epilepsy. Of the persons with epilepsy, 1,017 had a head injury prior to diagnosis.

Table 1 shows the “relative risk” for developing epilepsy after suffering each injury type. Relative risk is the probability of having a seizure after the injury divided by the probability of having a seizure without the injury. The exact risk can never be known with complete certainty because of measurement error present in any study. The confidence interval is the range in which the actual risk is likely to fall if measurement error could be eliminated.

Dire Findings
These results indicate that a typical person will be more than twice as likely to experience a seizure after a mild TBI and between 7.5 to 9 times as likely to have a seizure after a severe TBI. These are momentous findings, but the situation is actually worse for people older than 15 years of age, with a family history of epilepsy, or females. In older claimants, mild TBI increased the risk by 3.5 times and severe injury by more than 12 times. Patients with a family history of epilepsy are 6 times more likely to have a seizure after a mild injury and 10 times more likely after a severe injury. The risk for women is slightly higher in all groups.

Continuing Risk
This new reference study is also the first to clearly indicate the long-term epidemiological risk of developing epilepsy after TBI. As shown above in Table 2, the risk remains high for persons with severe injuries or skull fractures even 10 years after the TBI or skull fracture.

What Do We Do?
Tables 1 and 2 summarize the risk for a group of people. There is no easy way to predict the risk for a single claimant because the risk varies in a complex way that is influenced by age, injury severity, family history, and sex. There are no biomarkers that can predict which claimants will eventually develop epilepsy. There are no methods for continuously monitoring patients for the onset of seizure disorders. Video electroencephalography (EEG) remains the gold standard but is rarely conducted beyond 24-hours because of its high cost. Drug treatment started immediately after TBI is common, but its effectiveness in preventing post-traumatic epilepsy has not been impressive. Nonetheless, it is the only treatment currently available, and this forthcoming study indicates that it may need to be continued much longer than has typically been the case to date.

These results will be published in the Lancet this spring and gradually begin to influence clinical practice as physicians and neuropsychologists become aware of them. This might result in additional financial exposure for insurers. These risks should be considered when setting case reserves in a head injury case.