The Medical Burden of Drug-Resistant Epilepsy in an Outpatient Clinic of a Tertiary Hospital: A Prospective Study Based on Real-World Evidence.

OBJECTIVE: Drug-resistant epilepsy (DRE) leads to a range of medical and social consequences, which contribute to a high disease burden. We aimed to describe factors associated with an increased medical burden in DRE. METHODS: We designed a longitudinal prospective study including adult people with epilepsy (PWE) who visited at least once in an outpatient clinic of a tertiary hospital during 2023. Demographic and clinical data were collected. Emergency department (ED) consultations and antiseizure medications (ASM) were documented at each visit. Information comes from a structured data warehouse integrated into an electronic health record designed for the follow-up of PWE and used systematically in clinical practice. Patients were categorized into drug-responsive or drug-resistant epilepsy (DRE) according to the ILAE criteria. RESULTS: Of 2835 patients (51% men) and 4935 outpatient visits, 785 (27.7%) had DRE. Drug resistance was more common in focal epilepsy (29.7% vs. 19.6% in generalized epilepsy; p < 0.001), in younger patients (44.1 ± 17.8 vs. 51.1 ± 20.7 years; p < 0.001), and with a younger onset (24.3 ± 22.4 vs. 42.4 ± 26 years; p < 0.001). DRE accounted for a higher rate of outpatient consultations [median per patient/year: 2 (1-3) vs. 1 (1, 2); p < 0.001], ED consultations (25.5% vs. 16.9%; p < 0.001) and traumatic injury resulting from seizures (1.7% vs. 0.5%; p = 0.01). ASM changes were more frequent in DRE (61.1% vs. 32.2, %; p < 0.001). SIGNIFICANCE: Systematic data collection using electronic health records enables comprehensive identification of epidemiological and clinical factors associated with DRE. Earlier age at onset and focal epilepsy contribute to a higher disease burden, along with more frequent follow-up visits and increased adjustments in ASM.