Sudden Death

We invited all young adults working or studying at UK higher education institutions (HEIs) to participate in a closed, online study about sudden bereavement: the UCL Bereavement Study. We anticipated that using the email systems of large institutions would be the best means of accessing hard-to-reach groups, particularly those not normally accessing health services, and avoiding the biases associated with recruiting a help-seeking sample.18 (link) Sampling from a diverse range of colleges, universities, art and drama schools, and agricultural colleges offered unique access to a large defined sample of young adults.
All 164 HEIs in the UK in 2010 were invited to participate, following up non-responding HEIs to encourage broad socioeconomic and geographic representation. Over 20% of HEIs (37/164) agreed to take part, with a higher response (40%) from those classified as the more prestigious Russell Group of universities. This provided a sampling frame of 659 572 staff and students. All participants were invited to take part in a survey of ‘the impact of sudden bereavement on young adults’, with the aim of masking them to the specific study hypotheses. There was no accurate way of measuring response, as the denominator of bereaved people was not ascertainable using routine data or survey methods. The majority of participating HEIs agreed to send an individual email invitation with embedded survey link to each staff and student member. For reasons of sensitivity (recent staff/student deaths), 10 HEIs modified this strategy, for example, by emailing students only, using their weekly news digest email, or advertising via staff and student intranet.
Inclusion criteria were as follows: people aged 18–40 who, since the age of 10, had experienced sudden bereavement of a close friend or relative. The 18–40 age range was defined to reflect an under-researched group of great policy interest.16 (link) Early childhood bereavements were excluded to minimise recall bias and restrict our focus to adult cognitive processing of life events, using the age threshold for criminal responsibility in England and Wales. A close contact was defined as ‘a relative or friend who mattered to you, and from whom you were able to obtain support, either emotional or practical’. Sudden bereavement was operationalised as ‘a death that could not have been predicted at that time and which occurred suddenly or within a matter of days’. Exposure status was classified by responses to the question: ‘Since you were aged 10 have you experienced a sudden bereavement of someone close to you due to any of the following: (1) sudden natural death (eg, cardiac arrest, epileptic seizure, stroke); (2) sudden unnatural death (eg, road crash, murder or manslaughter, work accident); (3) suicide?’ Mode of death was defined subjectively by the respondent, and not by coroner's verdict or death certificate, as perception of bereavement type was the exposure of interest.
In the case of more than one exposure, we adopted a hierarchical approach favouring those bereaved by suicide, for whom we anticipated the lowest base rate. This group were classified as suicide bereaved regardless of other exposures. Those bereaved by more than one non-suicide sudden death were asked to relate their responses to whichever person they had felt closest to, with exposure status classified accordingly.
We estimated that a minimum of 466 participants would be required in any one group (two-tailed analysis; 90% power) to detect a doubling of the UK community prevalence of lifetime suicide attempt (6.5%) in young adult samples.19 We chose a relatively large effect size to reflect our comparison to a non-bereaved baseline, lacking prevalence figures for bereaved UK samples.

This meta-analysis was registered in PROSPERO (CRD42021260724). We followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines for this meta-analysis. Two independent investigators (Yang Wu and Wen-Tao Bi) performed the literature search using Medline, EMBASE databases and ClinicalTrials.gov. The computer-based searches included the keywords “macrolides,” “azithromycin,” “erythromycin,” “clarithromycin,” “roxithromycin,” “cardiac,” “heart,” “cardiovascular,” “death,” “stroke,” “myocardial infarction,” “acute coronary syndrome,” “ventricular tachycardia,” “arrhythmia,” “sudden cardiac death,” “cardiac arrest,” “torsades de pointes,” “sudden death,” and “mortality.”

We searched the Web of Science Core Collection databases, including the Science Citation Index and Social Science Citation Index, on October 1, 2022 to identify studies regarding SUDEP published from 2002 to 2022. The search strategy was (TS=sudden unexpected death in epilepsy OR TS=SUDEP) OR (TS=sudden unexpected death AND TS=epilepsy).

Using the IHME's “Global Burden of Disease” search engine, under causes of death, we used the search criteria of measures (deaths, incidence, and prevalence), locations (the six countries), age groups from early neonatal to 14 years, and the year 2019.⁹ Data were input into Apple Numbers spreadsheet software. Finally, we excluded sudden deaths and nondisease causes of death such as suicide and accidents.
Pediatric deaths attributable to known diseases or medical conditions were identified and grouped into five categories: neonatal conditions, infectious diseases, neoplastic diseases, congenital (including genetic) disorders, and other diseases. We then evaluated the different diseases and allocated them to the four groups described in the TFSL guide. Finally, an evidence-based approach was used to estimate children living with those fatal diseases (see Table 1). Data were analyzed and tabulated in Tables 2 and 3.