Abstracts

Epilepsy is a potentially life-threatening condition and carries an excess mortality as shown both in population-based and studies of more selected populations. Little, however, is known about life expectancy in people with this condition.
We estimated life expectancy in a cohort of people with newly diagnosed epilepsy in comparison to the general population. We used data from the UK National Practice Research Database (NGPSE), a prospective, population-based study of epilepsy. We have previously reported increased SMRs for all-cause mortality following a diagnosis of epilepsy up to a maximum of 14 years of follow-up (Lhatoo et al., Ann Neurol 2001; 49: 336-344). A cohort of 564 people has been followed up for nearly 15 years, a total of 7,147 person-years. During this period there were 177 deaths. These data excluding a subset of 38 subjects with brain tumours have been used to estimate the life expectancy of people in the cohort by employing a parametric survival model based on the Weibull distribution. Life expectancy in people with epilepsy was estimated as a function of age at, and time from diagnosis according to two broad aetiologic groups (idiopathic/cryptogenic and symptomatic). Estimates were then compared with life expectancy in people of the same age and sex in the general population according to the most recent life table, based on mortality in England and Wales centred on the census 1991.
The reduction in life expectancy is only minimal for people with idiopathic/cryptogenic epilepsy (less than 2 years at age 50 or over, and less than a year before age 30), who have about the same life expectancy as the general population if they survive 5 years after diagnosis. Women with symptomatic epilepsy lose 11, and men 13 years of life if diagnosed early in life (up to the age of 5 years). Reductions in life expectancy are highest at the time of diagnosis but diminish with time in both groups: about 10 years lost with diagnosis at age 20 or earlier and about 5 years lost at age 70 in people with symptomatic epilepsy. People with symptomatic epilepsy continue to experience a decreased life expectancy even after 20 years from diagnosis. There is a trend of diminishing number of years of life lost the longer someone survives and of a progressively increased percentage of normal life expectancy lost with advancing age at diagnosis. Men and women appear to suffer similar absolute reductions but men experience a slightly larger percentage reduction of normal life expectancy.
Our model shows that in people with newly diagnosed epilepsy higher mortality rates translate into a decrease in life expectancy, which is more pronounced in those with symptomatic epilepsy.
[Supported by: A.G. was supported by a grant from the [italic]National Society for Epilepsy[/italic]. The NGPSE has been supported by [italic]Action Research[/italic], the [italic]National Society for Epilepsy[/italic], and[italic] Brain Research Trust[/italic].]