First-Drug Efficacy and Drug-Resistant Epilepsy Rates in Children With New-Onset Epilepsies: A Multicenter Large Cohort Study.

Objective: This study aimed to assess the first-drug efficacy rate in newly diagnosed children with epilepsies treated with antiseizure medications. Methods: This retrospective study was conducted on 1003 children (age range: 3-10 years, and the mean duration of follow-up: 22 ± 13 months) with newly diagnosed epilepsy. The following parameters were evaluated: first-drug efficacy rate, first-drug-failure rate, and drug resistance rate in the cohort. Results: The first-drug-failure rate was defined in 335/1003 (33%) of the patients, no seizure control in 315 (31%), and drug withdrawal in 20 (2%). There was no significant difference between the group with focal-onset seizures and the group with generalized onset seizures. The first-drug efficacy rate was 67% in children with focal-onset seizures and 66% in children with generalized-onset seizures. Adjunctive antiseizure medication therapy was initiated in 335 patients-dual therapy with 180 patients (18%) and polytherapy with 155 (15%). Drug-resistant epilepsy was defined as 15% in the follow-up period. Etiology-specific diagnoses of the cohort were structural (n = 165, 17%), genetic (n = 25, 3%), metabolic (n = 15%), immune-infectious (n = 17 (2%), and unknown (n = 781, 77%). With a comparison of the 2 most common etiology subgroups (structural versus unknown), a first-drug efficacy rate of 53% and a higher prevalence of drug-resistant epilepsy at 30% were observed in children with structural etiology. First-drug efficacy was statistically lower in children without well-defined epilepsy syndromes (65%) compared with the rate of those with well-defined epilepsy syndrome (79%). Conclusion: This study revealed a first-drug failure rate (33%) in the presented cohort with a drug-resistance epilepsy rate (15%).