Prognostic Factors for Recurrence of Seizure After Antiepileptic Drug Withdrawal

ABSTRACT

BACKGROUND: Discontinuation of antiepileptic drug (AED) is valuable in patients of epilepsy who have been seizure free for a considerable time. However, there are few established methods to successfully stop AED. The purpose of study was to find the prognostic factors and the method of desirable AED withdrawal. METHODS: Seventy-eight patients who were seizure free for more than 18 months were enrolled in this retrospective study. The patients were followed for more than 2 years after starting withdrawal, or until seizure recurrence within 2 years. To clarify the prognostic factors affecting the seizure recurrence related to the withdrawal, statistical analyses were done about AED types, EEG before withdrawal, sex, age, onset age of seizure, febrile convulsion, family history, brain CT/MRI, trauma history, loss of consciousness history, seizure nature, and duration of seizure free. Furthermore, survival analysis between groups over the duration of withdrawal period and AED decrement rate was done to elucidate the most successful methods of AED withdrawal. RESULTS: Fifty-seven patients (73%) experienced seizure recurrence after starting withdrawal within 2 years. Over 12 months of withdrawal duration (p=0.037) and under 20 percent per month of the decrement rate of carbamazepine (p=0.019) were related to reduce the seizure recurrence. These were also confirmed via survival curve analysis. CONCLUSIONS: This study is a new attempt to apply reduction rate in withdrawal. AED withdrawal duration and decrement rate are important factor to prognostic factors of desirable AED withdrawal and minimize the recurrence after withdrawal.