NEW ORLEANS – according to data described at the annual meeting of the American Epilepsy Society. Whether this decrease resulted from an improved understanding of SUDEP risk or a focus on risk-reduction strategies is unknown, said Daniel Friedman, MD, associate professor of neurology at the New York University Langone Health.
In addition, the rates of SUDEP in various populations differ according to their socioeconomic status. Differences in access to care are a potential, but unconfirmed, explanation for this association, said Dr. Friedman. Another possible explanation is that confounders such as mental health disorders, substance abuse, and insufficient social support affect individuals’ ability to manage their disorder.
Dr. Friedman and colleagues initially examined SUDEP rates over time in a cohort of patients who received vagus nerve stimulator (VNS) implantation for drug-resistant epilepsy. They analyzed data for 40,443 patients who underwent surgery during 1988-2012. The age-adjusted SUDEP rate per 1,000 person-years of follow-up decreased significantly from 2.47 in years 1-2 to 1.68 in years 3-10. “There was no control group, so we couldn’t necessarily attribute the SUDEP rate reduction to the intervention,” said Dr. Friedman. A study by Tomson et al of patients with epilepsy who received VNS implantation had similar findings.
The literature about the mechanisms of SUDEP and reduction of SUDEP risk has increased in recent years. Neurologists have advocated for greater disclosure to patients of SUDEP risk, as well as better risk counseling. Dr. Friedman and his colleagues decided to investigate whether these factors have affected the risk of SUDEP during the past decade.
They retrospectively examined data for people whose deaths had been investigated at medical examiner’s offices in New York City, San Diego County, and Maryland. They focused on decedents for whom epilepsy or seizure was listed as a cause or contributor to death or as a comorbid condition on the death certificate. They reviewed all available reports, including investigator notes, autopsy reports, and medical records. Next, Dr. Friedman and his colleagues calculated the annual SUDEP rate as a proportion of the general population, estimated using annual Census and American Community Survey data. They used the Mann-Kendall test to analyze the trends in SUDEP rate during 2009-2015.
Of 1,466 deaths in people with epilepsy during this period, 1,124 were classified as definite SUDEP, probable SUDEP, or near SUDEP. Approximately 63% of SUDEP cases were male, and 45% were African-American. The mean age at death was 38 years.
Dr. Friedman’s group found a significant decrease in the overall incidence of SUDEP in the total population during 2009-2015. When they examined the three regions separately, they found decreases in SUDEP incidence in New York City and Maryland, but not in San Diego County. They found no difference in SUDEP rates by season or by day of the week.
In a subsequent analysis, Dr. Friedman and his colleagues adjudicated all deaths related to seizure and epilepsy in the three regions during 2009-2010 and 2014-2015 and identified all cases of definite and probable SUDEP. The estimated rate of SUDEP decreased by about 36% from the first period to the second period. SUDEP rates as a proportion of the total population in those regions also declined.
The investigators also examined differences in estimated SUDEP rates in the United States according to median household income. In New York, the zip codes with the highest SUDEP rates tended to have the lowest median household incomes. The zip codes in the lowest quartile of family household income had a SUDEP rate more than twice as high as that in the zip codes in the highest income quartile. This association held true for the period from 2009-2010 and for 2014-2015.
Dr. Friedman and colleagues received funding from Finding a Cure for Epilepsy and Seizures, which is affiliated with the NYU Comprehensive Epilepsy Center and NYU Langone Health.
SOURCE: Cihan E et al. AES 2018, Abstract 2.419.