Initial response to antiepileptic drugs in patients with newly diagnosed epilepsy.

This study aimed to identify factors predicting the response to antiepileptic drugs in patients with newly diagnosed epilepsy. We prospectively studied 176 patients with newly diagnosed epilepsy. Patients were included if they had a history of two or more clinically definite unprovoked seizures, or had a definite epileptic focus on MRI or epileptiform discharges on electroencephalography if they had suffered only one seizure. The primary endpoint was seizure freedom during the initial 6 months of antiepileptic drug treatment. The secondary endpoint was the time to the first seizure during the maintenance period of antiepileptic drug treatment. A total of 100 patients were included, and seizure freedom for 6 months was achieved in 73 patients. The response to antiepileptic drugs was significantly lower in patients with early age at seizure onset (⩽ 16 versus >16 years old, odds ratio=4; 95% confidence interval [CI] 1.5-12.9; relative risk=1.4; 95% CI 1.1-1.8). In addition, the time to the first seizure during the maintenance period was significantly earlier in patients with age at seizure onset ⩽ 16 years compared with those with age at seizure onset >16 years on the Kaplan-Meier survival analysis (p=0.011). Early age at seizure onset is an important factor influencing the response to antiepileptic drugs in patients with newly diagnosed epilepsy.