Mortality in patients with a first unprovoked seizure

The mortality after a first epileptic seizure is affected by the source of cases, the intensity of the diagnostic work-up, the type and the presumed etiology of the seizure, the length of follow-up, and the modalities of data collection (retrospective vs. prospective). We review the four studies of this topic.

Four studies have been identified which focused on the mortality of the first unprovoked seizures or the first afebrile (provoked or unprovoked) seizure. These included two population-based surveys, one clinic-based community survey, and a randomized clinical trial on the treatment of the first unprovoked generalized tonic-clonic seizure.

A standardized mortality ratio (SMR) of 2.3 (95% confidence interval, CI 1.5-3.3) for unprovoked first seizures was found in a retrospective cohort study in the population of Rochester, Minnesota. The SMR was higher during the first year after the seizures to progressively decrease thereafter. Acute symptomatic seizures carried the higher risk, followed by remote symptomatic seizures, while idiopathic and cryptogenic seizures carried no risk. The increased SMR found in women and in patients aged 0-19 years enrolled in the randomized trial differs from that seen in other mortality studies in epilepsy (SMR being highest in the youngest age groups) and may be a chance finding.

Mortality is increased in patients with a first unprovoked seizure, particularly during the first year after the seizure. This increased mortality is associated with known etiology of the seizure, and is not present when etiology is unknown.