Abstracts

Rationale: People with epilepsy have an increased risk of premature death compared with the general population. Most studies of mortality in epilepsy report overall standardized mortality ratios (SMR) between 2.0 and 4.0 (Watila MM et al. Overall and cause-specific premature mortality in epilepsy: A systematic review. Epilepsy & behavior: E&B. 2018;87:213-25), but the risk of death is found to be up to seven-fold higher in persons below 50 years of age (Thurman DJ et al. The burden of premature mortality of epilepsy in high-income countries: A systematic review from the Mortality Task Force of the International League Against Epilepsy. Epilepsia. 2017;58(1):17-26).The aim of this study was to evaluate the all-cause mortality in an unselected nationwide population of persons with epilepsy aged 1-49 years in Denmark in 2007-2009.. Methods: All Danish residents are assigned a unique personal civil registration number, which can be linked to national registries on an individual level. Residents aged 1-49 years in 2007-2009 were included in the study population. Persons registered with an epilepsy diagnosis in the Danish National Patient Registry within the last five years prior to the study period were defined as epilepsy patients. Information on all deaths in persons with epilepsy were extracted from the Danish Causes of Death Register, death certificates and autopsy reports, and were evaluated independently by three neurologists and one neuro-pediatrician in search for causes of death including sudden unexpected death in epilepsy (SUDEP). Results: The study population consisted of 3,588,339 persons followed for 10,401,741 person-years and with 7849 deaths during the study period. A total of 34,232 persons with prevalent epilepsy followed for 87,960 person-years and with 694 deaths were included in the study population. Crude all-cause mortality rates in persons with and without epilepsy were estimated to 7.9/1000 person-years and 0.7/1000 person-years, respectively, corresponding to a crude mortality hazard ratio between persons with and without epilepsy of 11.3 (CI95%: 10.5-12.3), p-value<0.0001. SMR between persons with and without epilepsy was estimated to 10.8 (CI95%: 10.0-11.6) p<0.0001.Crude all-cause mortality rates in males and females with epilepsy were estimated to 9.43/1000 person-years and 6.26/1000 person-years, respectively, corresponding to a crude mortality hazard ratio between males and females of 1.5 (CI95%: 1.4-1.6), p<0.0001). The three most frequent causes of death in persons with epilepsy were cancer, SUDEP and pneumonia comprising 27%, 16% and 14% of all deaths, respectively. Conclusions: This unselected nationwide study of all-cause mortality in young persons with epilepsy found an 11-fold higher rate of death compared with persons without epilepsy, and with the highest rate found in males. The mortality ratio in persons with epilepsy is comparable to results from previous studies in Denmark and Sweden, but higher compared with many other studies of mortality in epilepsy. This study focuses on the burden of epilepsy in the young and adds information of a high risk of premature death in persons with epilepsy below 50 years of age.Furthermore, SUDEP cases are difficult to find in registries. The high proportion of SUDEP in this cohort compared with other community-based studies might be explained by the reevaluation of all deaths. Funding: The Lundbeck Foundation