Abstracts

Rationale: To investigate the cumulative probability of at least one year of seizure remission among adult patients with medically intractable epilepsy, and to determine the probability of subsequent seizure relapse among those who achieved remission. Methods: A prevalence cohort of intractable adult epilepsy patients was identified from retrospective chart review of all patients seen in 2001 at the Columbia Comprehensive Epilepsy Center. Patients were included if they failed 2 adequate trials of antiepileptic medication and had more than one seizure per month for 3 months prior to an index visit in 2001. Outcome at a mean follow-up duration of 3.9 years was previously reported. The current study takes advantage of additional follow-up since our first study. Cumulative probabilities of seizure remission and subsequent seizure relapse were estimated using Kaplan-Meier analysis. Patients who underwent epilepsy surgery during follow-up were censored at the time of surgery. Cox proportional hazards models were used to assess the association between clinical factors and seizure remission as well as between clinical factors and seizure relapse. Results: One hundred eighty seven subjects with intractable epilepsy were identified from 1308 patients screened. At the index visit in 2001, subjects had mean age of 41 years and mean epilepsy duration 25.6 years. Mean follow-up was 5.9 (SD 2.4) years. At 8 years of follow-up the cumulative probability of seizure remission for more than one year was 22%, with estimated probability of remission about 3-4% per year. For most subjects, seizure remission was temporary, as 80% of subjects with remission relapsed by 5 years of follow-up. None of the clinical factors (history of status epilepticus, age of onset, developmental delay, etiology of epilepsy, mesial temporal sclerosis, history of febrile seizures, duration of epilepsy, number of failed AEDs, or history of epilepsy surgery) predicted the likelihood of achieving greater than one year seizure remission or subsequent seizure relapse. Conclusions: Although some patients with intractable epilepsy achieve more than one year of seizure remission during medical treatment, most of these patients eventually have seizure relapse. No clinical predictors of remission or subsequent relapse were identified. These results provide further support that medical management alone is unlikely to render patients who have previously failed 2 AEDs seizure-free in the long-term.