Patterns of Anti-Seizure Medication Utilization in the Human Epilepsy Project (HEP).

Abstract

To ascertain the natural history and patterns of anti-seizure medication (ASM) use in newly diagnosed focal epilepsy patients that were initially started on monotherapy. The data was derived from the Human Epilepsy Project. Differences between the durations of the most commonly first prescribed ASM monotherapies were assessed using a Cox proportional hazards model. Subjects were classified in three groups: monotherapy, sequential monotherapy and polytherapy. A total of 443 patients were included in the analysis with a median age of 32-years-old (IQR: 20-44) and median follow-up time of 3.2 years (IQR 2.4-4.2-). 161 (36.3%) patients remained on monotherapy with their initially prescribed ASM at the time of their last follow-up. The mean (SEM) and median (IQR) duration of time that patients stayed on monotherapy with their initial ASM was 2.1 (2.0-2.2) and 1.9 (0.3-3.5) years, respectively. The most commonly prescribed initial ASM was levetiracetam (254, 57.3%), followed by lamotrigine (77, 17.4%), oxcarbazepine (38, 8.6%) and carbamazepine (24, 5.4%). Among those who did not remain on the initial monotherapy, 167 (59.2%) transitioned to another ASM as monotherapy (sequential monotherapy) and 115 (40.8%) ended up on polytherapy. Patients remained significantly longer on lamotrigine (mean: 2.8 years, median: 3.1 years) compared to levetiracetam (mean: 2.0 years, median: 1.5 years) as a first prescribed medication (HR 1.5, 95% CI 1.0-2.2) . As the study progressed the proportion of patients on lamotrigine, carbamazepine and oxcarbazepine as well as other sodium channel agents increased from a little more than one-third (154, 34.8%) of patients to more than two-thirds (303, 68.4%) of patients. Slightly more than one-third of focal epilepsy patients remain on monotherapy with their first prescribed ASM. Approximately three-in-five patients transition to monotherapy with another ASM while approximately two-in-five end up on polytherapy. Patients remain on lamotrigine for a longer duration of time compared to levetiracetam when prescribed as the initial monotherapy.