Abstracts

RATIONALE: When epilepsy is in remission, it may be in the patient[ssquote]s best interest to discontinue medication. However, the optimal timing of AED discontinuation is not known. Therefore, we sought to quantify seizure relapse risk after early ([lt]2 seizure free years) versus late ([gt]2 seizure free years) withdrawal in adult and pediatric epilepsy patients and assess which variables modify the risk of seizure recurrence.
METHODS: MEDLINE, Index Medicus, CINAHL, EMBASE databases as well as hand searching for published abstracts in both English language and non-English journals were searched for trials involving AED withdrawal. Randomized controlled trials that evaluated withdrawal of antiepileptic drugs after varying periods of seizure remission in adult and pediatric epilepsy patients with or without blinding were included if they compared an early versus late antiepileptic drug discontinuation. Two reviewers independently extracted data and assessed trial quality. Relative risks with 95% confidence intervals were calculated for each trial. Summary relative risks and 95% confidence intervals for dichotomous data were calculated using a random effects model. A test of statistical heterogeneity was conducted for each pooled relative risk calculation.
RESULTS: Seven eligible controlled trials were included in the analysis representing 924 randomized pediatric patients. There were no eligible trials evaluating adult seizure free patients. The pooled relative risk for seizure relapse in children early ([lt] than 2 seizure free years) versus late AED (2 or more seizure free years) withdrawal was 1.32 (p=0.03,95% confidence interval 1.02 to 1.70). The pooled risk difference was 0.10(p=0.04,95% confidence interval of 0.00 to 0.20) for at least a 2-year followup. On the basis of this estimate, the number needed to harm is 10, that is, for every 10 patients that are withdrawn later off of AED, one seizure relapse is prevented compared to early withdrawal.When early discontinuation was employed, there were greater relapse rates in patients with partial seizures [pooled RR = 1.52; 95% confidence interval 0.95 to 2.41] or an abnormal EEG [pooled RR=1.67; 95% confidence interval 0.93 to 3.00].
CONCLUSIONS: There is evidence to support waiting for at least 2 or more seizure free years before discontinuing AEDs in children, particularly if individuals have an abnormal EEG and partial seizures. There is no evidence to guide the timing of early withdrawal of AEDs in adult seizure free patients. Further blinded randomized controlled trials are needed to identify the optimal timing of AED withdrawal and risk factors predictive of relapse.
Support: Sirven JI, Sperling MR. When can antiepileptic drugs be withdrawn in patients with epilepsy (protocol for Cochrane review)? In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software.