Drowning in people with epilepsy - How great is the risk?

Background: People with epilepsy are known to be at increased risk of death by drowning but there are few data available regarding the size of the risk. We aimed to quantify the risk using meta-analysis. Methods: A literature search identified 51 cohorts of people with epilepsy in whom the number of deaths by drowning in people with epilepsy and the number of person-years at risk could be estimated. Population data were taken from the WHO Statistical Information Service or from the UK Office for National Statistics where available. Standardized mortality ratios (SMRs) with 95% CIs were calculated for each cohort, for groups of cohorts, and for the total population. Additionally, an SMR for drowning in people with epilepsy in England and Wales (1999-2000) was calculated using National Registries. Results: Eighty-eight drowning deaths were observed compared with 4.70 expected, giving an SMR of 18.7 (95% CI 15.0 to 23.1). Compared with community-based incident studies (SMR 5.4), the SMR was significantly raised in prevalent epilepsy (SMR 18.0), in people with epilepsy and learning disability (SMR 25.7), in those in institutional care (SMR 96.9), and in those who had a temporal lobe excision (SMR 41.1). The SMR for people with epilepsy in England and Wales was 15.3. Conclusion: The risk of drowning in people with epilepsy is raised 15- to 19-fold compared with people in the general population. It is important that people with epilepsy and their carers be informed of these risks so that deaths can be prevented.