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The risk of premature mortality is similarly elevated in people with drug-resistant epilepsy28. In
a prevalent cohort of 433 people with drug-resistant epilepsy (at least one seizure per month
despite treatment with two or more AEDs), with median duration of epilepsy 25 years at study
entry who were followed up for six years, the cumulative probability of death was 8.7% (95% CI
6.2, 12.1) with an overall SMR of 2.4 (95% CI 1.7, 3.3). The mortality was largely driven by
those with a known epilepsy aetiology; the SMR was 3.1 (95% CI 2.0, 4.6) in people with a
remote symptomatic or progressive aetiology and 1.7 (95% CI 0.8, 2.8) in people with an
unknown aetiology). The excess mortality in those with known aetiology was not eliminated by
exclusion of those with progressive aetiology (SMR 2.5; 95% CI 1.4, 3.8).

Epilepsy-related deaths

Deaths directly related to epilepsy include SUDEP, status epilepticus, consequences of seizures
(including accidents, drowning and aspiration pneumonia), iatrogenic (drug toxicity and
idiosyncratic) and suicide.

The case fatality following status epilepticus typically ranges from 10−22%29 (Rochester 21%30),
with some lower case fatality rates in Europe, possibly as a result of the exclusion of deaths due
to status epilepticus following anoxic encephalopathy.

The primary determinant of prognosis in status epilepticus is aetiology31 but other factors such
as age and seizure duration are important in determining outcome32. There is some suggestion
that the case fatality following status epilepticus may be decreasing (although the evidence is
conflicting)33 and is particularly low in children34.

SUDEP is defined as a sudden, unexpected death in an individual with or without evidence of a
seizure where post mortem does not reveal a specific cause of death35. Estimates of SUDEP rates
are heavily influenced by the population under study, with much higher rates in those with severe
or refractory epilepsy. Identified risk factors for SUDEP include younger age of onset, long
duration of epilepsy and refractory epilepsy36. The incidence of SUDEP was 0.35 per 1000 person
years in the Rochester cohort37, while an incidence of 1:295 per year was found in children with
more severe epilepsy and learning difficulties38. SUDEP is reviewed in greater detail in Chapter
38.

People with epilepsy may die as a result of an accident during a seizure. Based on attendance
records of four accident and emergency (A&E) departments, the risk of injury as a result of a
seizure was estimated to be 29.5 per 100,000 population per year39. Many seizure-related injuries
tend to be minor, with an increased risk related to background seizure frequency40, but some
injuries can be fatal.

In a one-year population-based study (using inpatient records, doctors’ claims and A&E visits)
the annual incidence of injuries was higher in people with epilepsy, with 20.6% of people with
epilepsy having at least one injury compared with 16.1% among people without epilepsy (P <
0.001). In particular, people with epilepsy were more likely to have fractures, crushing injuries,
intracranial and other head injuries41. Similarly over a two-year period, people with epilepsy were
more likely to have injuries inflicted on them by others (odds ratio 1.46; 95% CI 1.04, 2.03) after
adjustment for co-morbidities; they were slightly more likely to have motor vehicle accidents and
completed or attempted suicide42.