Predictors for relapse after antiepileptic drug withdrawal in seizure-free patients with epilepsy.

The objective of this study was to evaluate the timing of medication withdrawal and other clinical factors as potential predictors of seizure relapse after antiepileptic drug (AED) withdrawal in patients with epilepsy. A total of 99 patients who were seizure free for more than 2 years were recruited from the Neurology Clinics of Nanjing Brain Hospital between 2001 and 2009, and were followed prospectively for at least 2 years or until seizure relapse. Kaplan-Meier survival analysis was used for calculating recurrence rates. Univariate and multivariate analyses for recurrence risk factors were performed using the Cox proportional hazards model. Thirteen patients were excluded due to loss of follow-up or incomplete seizure records. Epileptiform electroencephalography (EEG) abnormality within the first year after AED withdrawal (hazard ratio [HR] = 4.810, 95% confidence interval [CI] = 2.220-10.420) was found on multivariate analysis to be a predictor of seizure recurrence. Early AED withdrawal after a seizure-free period of 2-3 years did not significantly increase the risk of recurrence (HR = 0.999, 95% CI = 0.969-1.029) as compared with delayed AED withdrawal (patients who were seizure-free for more than 3 years). AED can be withdrawn in patients who have been seizure-free for more than 2 years. As epileptiform EEG abnormality within the first year after AED withdrawal predicts seizure relapse, it is necessary to perform EEG for patients during the first year after AED withdrawal.