Risk of recurrence after drug withdrawal in childhood epilepsy

After a reasonable seizure-free period, discontinuation of antiepileptic drugs (AED) is usually decided in epileptic patients despite the risk of seizure recurrence. In children, risk of recurrence after discontinuation of AED is generally 20-40%; however, there is still no general agreement on the criteria to predict safe discontinuation. This study was designed to determine the risk of recurrence and related risk factors after drug withdrawal in epileptic children.

200 epileptic patients between 1 month and 15 years of age who were followed at least 1 year after drug withdrawal at a child neurology center between January 1993 and December 2005 formed the study population of this retrospective study. Patients were classified into groups according to defined risk factors for recurrence.

Of 200 patients (118 boys, 82 girls), overall recurrence rate was 27%. Girls were more likely to have a seizure recurrence than boys, with the difference approaching statistical significance (p=0.058). EEG recordings after withdrawal (post-withdrawal EEG) in the follow-up were significantly different in the patients with recurrence with respect to presence of an abnormality (p=0.05). In the multivariate Cox regression analysis, female gender and abnormal post-withdrawal EEG were the risk factors influencing seizure recurrence, with female gender identified as the main risk factor.

Although the decision to discontinue AED treatment necessitates evaluation of each patient individually, our study suggests that female patients and those with abnormal EEG after withdrawal require more cautious follow-up because of the high risk of recurrence.