Tuesday, September 29, 2020

Socioeconomic disparities in SUDEP. Declining rate of SUDEP.

Cihan E, Hesdorffer DC, Brandsoy M, Li L, Fowler DR, Graham JK, Karlovich M, Donner EJ, Devinsky O, Friedman D. Socioeconomic disparities in SUDEP in the US. Neurology. 2020 Jun 16;94(24):e2555-e2566. doi: 10.1212/WNL.0000000000009463. Epub 2020 Apr 23. PMID: 32327496; PMCID: PMC7455330.


Objective: To determine the impact of socioeconomic status (SES) on sudden unexpected death in epilepsy (SUDEP) rates. 

Methods: We queried all decedents presented for medico-legal investigation at 3 medical examiner (ME) offices across the country (New York City, Maryland, San Diego County) in 2009 to 2010 and 2014 to 2015. We identified all decedents for whom epilepsy/seizure was listed as cause/contributor to death or comorbid condition on the death certificate. We then reviewed all available reports. Decedents determined to have SUDEP were included for analysis. We used median income in the ZIP code of residence as a surrogate for SES. For each region, zip code regions were ranked by median household income and divided into quartiles based on total population for 2 time periods. Region-, age-, and income-adjusted epilepsy prevalence was estimated in each zip code. SUDEP rates in the highest and lowest SES quartiles were evaluated to determine disparity. Examined SUDEP rates in 2 time periods were also compared. 

Results: There were 159 and 43 SUDEP cases in the lowest and highest SES quartiles. ME-investigated SUDEP rate ratio between the lowest and highest SES quartiles was 2.6 (95% confidence interval [CI] 1.7-4.1, p < 0.0001) in 2009 to 2010 and 3.3 (95% CI 1.9-6.0, p < 0.0001) in 2014 to 2015. There was a significant decline in overall SUDEP rate between the 2 study periods (36% decrease, 95% CI 22%-48%, p < 0.0001). 

Conclusion: ME-investigated SUDEP incidence was significantly higher in people with the lowest SES compared to the highest SES. The difference persisted over a 5-year period despite decreased overall SUDEP rates.

Cihan E, Devinsky O, Hesdorffer DC, Brandsoy M, Li L, Fowler DR, Graham JK, Karlovich MW, Yang JE, Keller AE, Donner EJ, Friedman D. Temporal trends and autopsy findings of SUDEP based on medico-legal investigations in the United States. Neurology. 2020 Aug 18;95(7):e867-e877. doi: 10.1212/WNL.0000000000009996. Epub 2020 Jul 7. PMID: 32636323.


Objective: To determine time trends and distinguishing autopsy findings of sudden unexpected death in epilepsy (SUDEP) in the United States. 

Methods: We identified decedents where epilepsy/seizure was listed as cause/contributor to death or comorbid condition on the death certificate among all decedents who underwent medico-legal investigation at 3 medical examiner (ME) offices across the country: New York City (2009-2016), San Diego County (2008-2016), and Maryland (2000-2016). After reviewing all available reports, deaths classified as definite/probable/near SUDEP or SUDEP plus were included for analysis. Mann-Kendall trend test was used to analyze temporal trends in SUDEP rate for 2009-2016. Definite SUDEPs were compared to sex- and age ±2 years-matched non-SUDEP deaths with a history of epilepsy regarding autopsy findings, circumstances, and comorbidities. 

Results: A total of 1,086 SUDEP cases were identified. There was a decreasing trend in ME-investigated SUDEP incidence between 2009 and 2016 (z = -2.2, S = -42, p = 0.028) among 3 regions. There was a 28% reduction in ME-investigated SUDEP incidence from 2009 to 2012 to 2013-2016 (confidence interval, 17%-38%, p < 0.0001). We found no correlation between SUDEP rates and the month of year or day of week. There was no difference between SUDEP and non-SUDEP deaths regarding neurodevelopmental abnormalities, pulmonary congestion/edema, and myocardial fibrosis. 

Conclusions: There was a decreasing monotonic trend in ME-investigated SUDEP incidence over 8 years, with a 28% reduction in incidence from 2009-2012 to 2013-2016. Unlike SIDS and sudden cardiac death, we found no correlation between SUDEP and the season of year or day of week. No autopsy findings distinguished SUDEP from non-SUDEP deaths.

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.


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