Presence of epileptiform discharges on initial EEGs are associated with failure of retention on first antiepileptic drug in newly diagnosed cryptogenic partial epilepsy: A 2-year observational study

OBJECTIVES Approximately two-thirds of the patients with newly diagnosed partial epilepsy remained on their first antiepileptic drug (AED) for 2 years in clinical practice. We aimed to analyze retention on the first AED for 2 years in newly diagnosed cryptogenic partial epilepsy patients in clinical practice and whether the presence of epileptiform discharges on the initial EEG was a predictor of the failure of retention on the first AED. METHODS For the purpose of this study, we retrospectively reviewed epilepsy database. On the Epilepsy Database, we found 495 newly diagnosed epilepsy patients who had been followed up for at least 2 years. Of these 495 newly diagnosed epilepsy patients, 172 patients had cryptogenic partial epilepsy. The outcome of this study was the retention rate for the first AED for 2 years. In addition, we analyzed the retention on first AED according to the presence or absence of epileptiform discharges on the initial EEG using Kaplan-Meier survival analysis. RESULTS Overall, retention rate on the first AED for 2 years was 51%. The main lesion of retention failure was a lack of tolerance. The presence of epileptiform discharges on the initial EEGs was significantly related to the failure of retention on the first AED (p=0.003). CONCLUSIONS In newly diagnosed cryptogenic partial epilepsy, overall retention on the first AED was not significantly different from that in newly diagnosed partial epilepsy. In clinical practice, epileptiform discharges on the initial EEG could predict the failure of retention on the first AED for 2 years.