People with epilepsy are 10 times more likely to die before their mid-fifties compared with the general population, according to a large study by researchers at Oxford University and the Karolinska Institutet in Sweden.
The findings reveal a striking correlation between premature death and mental illness in these patients. People with epilepsy were four times more likely to have received a psychiatric diagnosis compared with the general population.
The figures are considerably higher than previously thought and have important implications for epilepsy management. The study was part-funded by the Wellcome Trust and is published in the Lancet medical journal.
The researchers studied health data for almost 70,000 people with epilepsy born in Sweden between 1954 and 2009. Using data over 41 years from 1969 to 2009, the researchers compared mortality and cause of death information for these patients with over 660,000 people from the general population, matched for age and gender.
The study also looked at the unaffected brothers and sisters of those with epilepsy in order to rule out the influence of shared background factors such as genetic risk factors and upbringing.
Throughout the course of the study, 8.8% of people with epilepsy died, compared with 0.7% of people from the general population.
The most important cause of death in people with epilepsy that was not clearly related to the underlying disease process was death by external causes, such as accident or suicide. These accounted for almost 16% of deaths. Three quarters of these deaths were amongst patients who also had a psychiatric diagnosis.
Although suicide and deaths from accidents were still relatively rare, the odds of a person with epilepsy committing suicide during the study were four times higher than the general population, and there was a strong correlation with mental illness and substance abuse.
'This is the largest report to date to look at psychiatric associations in epilepsy and their contribution to premature mortality,' said Dr Seena Fazel, a Wellcome Trust Senior Clinical Research Fellow at the University of Oxford and the main author of the study. 'Our finding that three quarters of suicide and accident deaths in epilepsy also had a diagnosis of mental illness strongly identifies this as a high-risk population to focus preventative strategies and more intensive treatment on.
'Improving the identification, monitoring and treatment of psychiatric problems in epilepsy patients could make an important contribution to reducing the risk of premature death that we're currently seeing in these patients.'
The study also reveals that the odds of dying in a non-vehicle accident, such as drug poisoning or drowning, were more than five times higher for people with epilepsy than control populations.
'Our findings also highlight general accidents as a major, preventable cause of death in epilepsy patients and suggest that specific warnings, in addition to those already given around driving, should be provided to patients at the time of diagnosis to ensure they are aware of the risks,' added Dr Fazel.
Professor Charles Newton from the Department of Psychiatry at Oxford University said: 'Although it is well-recognised that psychiatric and addiction disorders occur in epilepsy, in high-income Western countries, epilepsy is often managed by neurologists only. The findings from this study would suggest that clinical epilepsy services should review their liaison with psychiatric and addiction services as a priority.'
This is the first study to look at the odds of premature death in people with epilepsy compared with their unaffected siblings, finding a similar difference in risk as the comparison to the general population. This provides further evidence that epilepsy as a disease is an independent risk factor for death by any cause.
The study was funded by the Wellcome Trust, the Swedish Prison and Probation Service and the Swedish Research Council.