Why Are Cases of SUDEP Declining?

Andrew N. Wilner, MD; Daniel Friedman, MD


September 23, 2020

This transcript has been edited for clarity.

Andrew N. Wilner, MD: Welcome to Medscape. I'm Dr Andrew Wilner. Today I have a special guest, Dr Daniel Friedman, professor of neurology at New York University medical school and the author of a paper that caught my eye in the journal Neurology on sudden unexplained death in epilepsy (SUDEP). Welcome, Dr Friedman.

Daniel Friedman, MD: Thank you for having me.

Wilner: SUDEP is something that's been around for a long time. Can you define it for us?

Friedman: SUDEP has been around for a while. In fact, there are even descriptions of SUDEP in George Washington's diary. His niece passed away from what was presumably SUDEP.

SUDEP is not a single entity. It's better described as a phenomenon when a person with epilepsy, who is otherwise in good health apart from their seizures, dies suddenly and unexpectedly and not due to status epilepticus or prolonged seizure.

The causes are thought to be myriad, but most evidence points to the fact that the death occurs soon after a seizure. Most of the evidence we have, which comes from witnessed cases of these deaths, are that SUDEP follows a tonic-clonic seizure.

Wilner: And one idea is, if you want to avoid SUDEP, avoid convulsions?

Friedman: Correct. The evidence bears that out. People who are having ongoing convulsions, more than three convulsive seizures a year, appear to be at highest risk for SUDEP, whereas those who have no convulsions are at the lowest risk. If you take somebody who is having ongoing convulsive seizures and perform epilepsy surgery or change their treatment, or add on a new and efficacious antiseizure medication, their risk for SUDEP goes down.

Wilner: SUDEP is hard to study because it's rare. What did you find in your paper?

Friedman: Exactly. When you are looking at geographic, demographic, and temporal trends to identify risk factors for SUDEP, you really have to look at populations. We looked at three large medical examiner offices in San Diego county, Maryland, and New York City, which together encompass a population of over 20 million people.

We found two major things. One is that, as in many other health outcomes, there are disparities in SUDEP rates between the lowest and highest socioeconomic bracket. We looked at the zip code of the person who died from SUDEP and estimated the community socioeconomic status. We found that patients who lived in a community that was in the lowest quartile of mean family income had a SUDEP rate two to three times higher than those in the top quartile. That disparity persisted over 5 years. We looked at the rates of SUDEP in 2009 and 2010 in these medical examiner offices and then again in 2014 and 2015.

What did change between those two time periods, which was the other interesting finding, is that the overall rate of SUDEP actually declined by about 30%. That's important because during that time period, we've had no specific intervention to address SUDEP, no introduction of new seizure medications that are any more efficacious than prior ones. The practice of epilepsy surgery has been well established in these communities for many years. Therefore, something is going on at a population level that is reducing the rates of SUDEP. I think the disparities exist and we need to identify their causes and perhaps create targeted interventions.

There is good news in that we've been able to observe a decrease in the rate of SUDEP over time, at least in these communities. We have a companion paper that was just published in Neurology that looks at temporal trends in SUDEP over an 8-year period in more granular detail. It confirms our finding that SUDEP rates have been decreasing over the past decade.

We can measure differences between communities over time and identify differences if we look on a population level with data that's already at hand, medical examiner reports. That's important if we want to create and test policy or public health interventions to improve epilepsy care, epilepsy treatment, and epilepsy-related mortality, as well as measure it.

Wilner: To recap, there were two major findings of your paper. The first was that if you're in a low socioeconomic class vs high, your risk for SUDEP is two to three times increased. We don't know exactly why; it's just an objective finding. Second, over time, the overall incidence of SUDEP has decreased by about a third.

The first finding isn't surprising. People who have trouble taking care of themselves because of low income often do worse in terms of healthcare, and we see that in many, many areas. But usually when we raise the level of awareness of an unusual disorder, the frequency increases because people are looking for it, they're educated about it, and you see a bump. But in fact, you've seen the opposite. I thought it was very interesting in your paper that you suggested that maybe this is because more people had health insurance and were able to take care of themselves. I think that that's really an important message.

Friedman: I think so. All three jurisdictions that we looked at had expansion of Medicaid under Obamacare. So in those areas there probably was increased insurance and increased ability to get medications, specialist referrals, and all of those things. That's going to be hard to tease apart without finding control medical examiner offices that didn't participate in Medicaid expansion.

Another thing that happened along this time period was that there actually was greater awareness among neurologists of SUDEP and perhaps better counseling, better recognition that people with intractable epilepsy are at risk for SUDEP, and more appropriate referrals to specialty centers, medication adjustments, and not being not willing to settle for ongoing seizures. There may have been a change in practice among neurologists caring for these patients and the community as well that was driven primarily by increased awareness.

During the same time period, there was a significant increase in publications about SUDEP, talks at the American Academy of Neurology or epilepsy meetings, and funding from the National Institutes of Health to tackle SUDEP. So that generally raises awareness in the community, and hopefully that changes practice too.

Wilner: Dr Friedman, I want to thank you very much for sharing your recent findings. It comes from hard work, covering three major cities and a lot of data points, I'm sure.

Friedman: Thank you for your interest.

Wilner: I'm Dr Andrew Wilner, reporting for Medscape.

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