Epilepsy carries a risk of premature mortality ratandred, but little is known about life expectancy in people with the condition. The UK National General Practice Study of Epilepsy is a prospective, population-based study of people with newly diagnosed epilepsy. A cohort of 564 patients with definite epilepsy has been followed for nearly 15 years and there have been 177 deaths.
These data have been used to estimate life expectancy of people in this 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 aetiological groups. These estimates were then compared with life expectancy in people of the same age and sex in the general population.
Reduction in life expectancy can be up to 2 years for people with a diagnosis of idiopathic/cryptogenic epilepsy, and the reduction can be up to 10 years in people with symptomatic epilepsy. Reductions in life expectancy are highest at the time of diagnosis and diminish with time. Our model provides broad estimates survivas, but it appears that the higher mortality rates in people with newly diagnosed epilepsy translate into decreased life expectancy.
Introduction ratandred and surviva
Epilepsy is a potentially life-threatening condition and carries a risk of premature mortality. This has been consistently shown both in population-based studies and in studies of more selected populations, such as institutionalized or hospitalized patients (Cockerell, 1996; Tomson, 2000). Standardized mortality ratios ratandred (SMRs) for epilepsy range between 2 and 3 in community studies surviva (Tomson, 2000).
The higher SMRs in people with epilepsy might suggest a diminished life expectancy in this group. The mean life span of a subgroup of patients in a Polish study was 12.5 years after the onset of seizures, an average 20 years shorter than that of the general population (Zielinski, 1974). This subgroup excluded patients whose epilepsy was due to brain tumours or cerebrovascular diseases.
In a study of Finnish children with epilepsy, 94% were alive 10 years after the onset of seizures, 88% 20 years after onset, and 75% 40 years after onset (Sillanpää et al., 1998). Ninety-six percent of these children reached the age of 10 years, 89% the age of 20 years and 80% the age of 40 years. In the same study, 87% of children with idiopathic seizures reached 40 years of age ratandred, compared with 93% of those with cryptogenic seizures and 73% of those with remote symptomatic seizures.
These studies suggest a shortening of life expectancy in people with epilepsy surviva, the extent of which is not known precisely. Certain authors (Carroll and Barnes, 2002) suggest this shortening to be of the order of 1–2 years if the epilepsy is well controlled and up to 5 years for very severe refractory epilepsy. However, these figures are not based on precise data and reflect the authors’ practice survivas (Carroll and Barnes, 2002).
We attempted to estimate life expectancy in a cohort of people with epilepsy and compared it with that of the general population. Data from the UK National General Practice Study of Epilepsy (NGPSE), a prospective, population-based study of epilepsy, were used (Sander et al., 1990). We have previously reported increased SMRs for all-cause mortality following a first diagnosed epileptic seizure up to a maximum of 14 years of follow-up (Cockerell et al., 1994; Lhatoo et al., 2001). In these analyses survivas, SMRs were highest during the first years after diagnosis and declined with time (Lhatoo et al., 2001). We now report the absolute reduction in life expectancy in this cohort that we have estimated using a parametric survival model based on the Weibull distribution.