Elsevier

Epilepsy & Behavior

Volume 76, November 2017, Pages 76-83
Epilepsy & Behavior

Incidence of sudden unexpected death in epilepsy in community-based cohort in China

https://doi.org/10.1016/j.yebeh.2017.08.024Get rights and content

Highlights

  • It was a large prospective study estimating the incidence of SUDEP in China.

  • We attempted to improve SUDEP diagnosis in resource-poor settings.

  • Our results suggest that SUDEP may kill over 20,000 people in China every year.

Abstract

Objective

Sudden unexpected death in epilepsy (SUDEP) is associated with the high premature mortality observed among people with epilepsy. It is, however, considered a rare event in China, probably because of lack of awareness and limitation of studies in the country. We aimed to provide some initial estimation of the burden of SUDEP in China.

Methods

We established a large Chinese community-based cohort of people with epilepsy between January 2010 and December 2011. For any participant who died during follow-up, detailed information on cause of death was obtained using a specifically designed Verbal Autopsy Questionnaire. All cases were reviewed by a multidisciplinary expert panel and reinvestigated if necessary. Sudden unexpected death in epilepsy incidence rates were estimated and case details provided.

Results

The cohort consisted of 1562 people and during a median 5 years follow-up, 72 deaths were reported. The all-causes death incidence was 11.23 (95% CI 8.86–14.07) per 1000 person-years. Fifteen died suddenly and unexpectedly in a reasonable state of health in the week preceding death. We recorded detailed information of these 15 deaths. Thirteen were considered to be probable SUDEP and two possible SUDEP. The incidence of probable SUDEP was 2.03 (95% CI 1.13–3.38) per 1000 person-years, and the incidence of all suspected (probable and possible) SUDEP was 2.34 (95% CI 1.36–3.77) per 1000 person-years.

Significance

The incidence of SUDEP was relatively high among Chinese people with epilepsy when compared with that in previous community-based studies from high-income countries. The burden of SUDEP in China requires further assessments.

Introduction

Sudden unexpected death in epilepsy (SUDEP) is associated with the premature mortality seen among people with epilepsy. In western countries, the incidence of SUDEP varies with the sample population, increasing from 0.35 to 2.3 in community samples to 1.1 to 5.9 in epilepsy clinics and between 6.3 and 9.3 in participants of epilepsy surgery programs [1]. One long-term study reported that in a cohort of people with epilepsy followed for over 30 years, SUDEP accounted for a third of all death [2].

There have been some Chinese case reports of SUDEP with autopsy but overall studies of SUDEP are still limited in China where there are over 9 million people with epilepsy [3].Only two prospective mortality studies have been reported from China [4], [5]; and they did not estimate SUDEP incidence making comparisons with reports from other countries difficult. The large variation in the proportional mortality ratios for SUDEP (14.7% [4] and 1% [5]) between these two studies suggests some methodological shortcomings in the diagnosis of SUDEP. Autopsies are rarely acceptable in Asia particularly in China and this compounds the issue.

We attempted to estimate the incidence of SUDEP in a Chinese population using specifically designed instruments to overcome some of the shortages and to report detailed information about cases identified.

Section snippets

Study cohort with epilepsy

Between January 2010 and December 2011, people with epilepsy were recruited from rural areas in the Chinese provinces of Henan, Shanxi, and Ningxia, as a part of the “Validation of Clinical Assessment Tools for Population Genetic Studies of Epilepsy (1R21NS069223-01, NIH/NINSD)”. All people with epilepsy aged 2–80 years were eligible for inclusion; they were, however, excluded for the following reasons: 1) if they had nonepileptic attack disorder, 2) if their seizures were related to alcohol or

Characteristics of subjects at the baseline and follow-up

A total of 1562 people were enrolled (baseline clinical and demographic characteristics provided in Table 1. Sixty percent were on antiepileptic drug (AED) monotherapy, and only 20% were in one-year remission when enrolled. A study flowchart is provided in Fig. 1. We were unable to determine survival status of 105 people in both two follow-ups thus the lost-to-follow up rate was 6.7%. No significant differences were found for baseline characteristics between those who were followed and those

Discussion

In this prospective community-based Chinese study, we identified cases of SUDEP and estimated a relatively high incidence for SUDEP. Studies from high-income countries suggest that SUDEP is responsible for up to a third [2], [10], [11], [12] of deaths and its leading cause of epilepsy-related death [2]. There are little data concerning SUDEP in China as only two studies have reported the proportional mortality ratios of SUDEP in epidemiological studies. A study from West China reported 15

Conclusion

There are over nine million people with epilepsy in China. Our results suggest that SUDEP may kill over 20,000 people yearly. Further prospective Chinese studies with larger sample size and longer follow-up periods are urgently needed to examine risk and protective factors in order to seek proper interventions to reduce the burden of SUDEP.

The following are the supplementary data related to this article.

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Author disclosures

YG, DD, BY, QZ, TW, WW, BL, JW, JL, PK, and ZH report no disclosures; JWS has received research funding from Eisai, GSK and UCB, personal fees from Eisai, UCB Lundbeck, and Teva, outside the submitted work.

Ethical publication statement

We confirm that we have read the journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Acknowledgments

We thank all the village physicians for their hard field work of follow-up, and all participants for their cooperation. JWS is based at UCLH/UCL Comprehensive Biomedical Research Centre, which receives a proportion of funding from the UK Department of Health's National Institute for Health Research Biomedical Research Centers funding scheme. He receives support from the Dr. Marvin Weil Epilepsy Research Fund and UK Epilepsy Society. This study was funded by National Natural Science Foundation

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