Supplementary Material for: Mortality of epilepsy in Chinese populations: a comprehensive review

Background: Premature mortality is a significant part of the epilepsy burden and may vary across populations, especially between high-income and lower- and middle-income countries. People with epilepsy in China are approximately a fifth of the global population with epilepsy. Previous studies were unlikely to represent the situation in China due to limitations in design, methods, sample size, follow-up time, and other inherent population heterogeneity.
Summary: By summarising the evidence on the mortality characteristics in Chinese populations with epilepsy in the last six decades, we found a median mortality rate of 14.7 (6.8-74.4)/1000 person-years and a median standardised mortality ratio (SMR) of 4.4 (2.6-12.9) in population-based studies, and a median mortality rate of 12.3 (9.5-101.5)/1000 person-years and a median SMR of 3.0 (1.5-5.1) in hospital-based studies. Vascular diseases, complications of diabetes, and accidental injuries were the leading causes of death. Risk factors for mortality were reported as older age, male, longer duration and higher frequency of seizures. Case fatality ratios of status epilepticus (SE) in adults were higher than in children, and both increased with follow-up time. Mortality in people with symptomatic epilepsy was high and varied across different primary diseases.
Key Messages: The highest mortality rate and sudden unexpected death in epilepsy (SUDEP) incidence were reported from the least developed areas in China. Accidental injuries were the most common causes of epilepsy-related deaths, while the incidence of SUDEP may be underestimated in Chinese populations. Further research is warranted to improve the understanding of premature mortality risk so that preventative measures can be introduced to improve the situation.

研究背景：过早死亡是癫痫疾病负担的重要组成部分，且在不同人群中存在显著差异，尤其体现在高收入国家与中低收入国家之间。中国癫痫患者人数约占全球癫痫患者总数的五分之一。既往研究受限于研究设计、方法学、样本量、随访时长以及固有人群异质性等因素，难以反映中国癫痫患者的实际疾病状况。
研究总结：本研究对近六十年来中国癫痫患者死亡特征的相关证据进行了汇总分析，结果显示，在以人群为基础的研究中，癫痫患者的死亡中位数率为14.7（6.8~74.4）/1000人年，标准化死亡率比（standardised mortality ratio, SMR）中位数为4.4（2.6~12.9）；在以医院为基础的研究中，死亡中位数率为12.3（9.5~101.5）/1000人年，SMR中位数为3.0（1.5~5.1）。血管疾病、糖尿病并发症以及意外伤害是癫痫患者的主要死亡原因。已知的死亡危险因素包括高龄、男性、癫痫发作病程更长及发作频率更高。成人癫痫持续状态（status epilepticus, SE）的病死率高于儿童，且二者的病死率均随随访时长增加而升高。症状性癫痫患者的死亡风险较高，且不同原发疾病对应的死亡风险存在差异。
核心结论：中国欠发达地区的癫痫患者死亡率与癫痫猝死（sudden unexpected death in epilepsy, SUDEP）发生率均为全国最高。意外伤害是癫痫相关死亡的最常见原因，而中国人群中SUDEP的发生率可能被低估。未来仍需开展进一步研究以加深对过早死亡风险的认识，从而制定针对性预防措施以改善当前现状。