Abstracts

Rationale: In the United States, epilepsy affects approximately 5 in 1,000 individuals. However, in the US Veteran population, the incidence of epilepsy is much higher at approximately 16 in 1,000 individuals. Epilepsy is associated with a reduced quality of life, higher rate of premature death, increased injuries and psychological illnesses. The goal of epilepsy treatment is to decrease or stop seizures while minimizing side effects of Anti-Epileptic Drugs (AEDs). Choice of AEDs is based primarily on seizure type, side effect profile, and patient preference. Multiple studies examining the retention rates of AEDs in patients with epilepsy have been conducted. The focus of retention studies is to examine the efficacy and tolerability of AEDs. There is a paucity of information on the discontinuation rates of AEDs and the reasons for discontinuation. The objective of our study is to determine which AEDs were most likely to be discontinued in veterans with focal onset epilepsy and to determine the possible reasons that lead to the discontinuation. Methods: We conducted a retrospective chart review of all veterans with a diagnosis of focal onset epilepsy seen in Seizure Clinic at the West LA VA from 7/1/2008 to 6/30/17. Baseline characteristics and the following data points were collected: presence of traumatic brain injury (TBI), discontinued AEDs, and reason for discontinuation. Results: We screened 463 patients and 242 patients met the inclusion criteria. Mean age of the veterans was 60, and the majority of the veterans were male (93%) with 51% having a history of TBI. The top 3 discontinued AEDs were phenytoin (PHT), valproic acid/valproate (VPA), and levetiracetam (LEV). Of the 179 patients tried on PHT, 149 were discontinued with 49 (34%) for unknown reason, 43 (31%) for side effects, 29 (20%) for inadequate efficacy, 12 (9%) for patient/provider preference, and 8 (5%) for “other” reason and 8(5%) for multiple reasons. Of the 90 patients tried on VPA, 68 were discontinued with 24 (33%) for unknown reason, 24 (33%) for side effects, 10 (14%) for inadequate efficacy, 6 (8%) for “other” reason, 3 (4%) for patient/provider preference and 1 (1.5%) for multiple reasons. Of the 168 patients tried on LEV, 61 patients were discontinued with 30 (49%) for side effects, 16 (26%) for “other” reasons, 7 (11.5%) for patient/provider preference, 4 (6.5%) for inadequate efficacy, 2 (3%) for unknown reasons and 2 (3%) for multiple reasons.   Conclusions: Our study evaluated the rate of discontinuation of AEDs and the reasons for discontinuation of those AEDs. We found that PHT, VPA, and LEV were the top 3 AEDs discontinued in our cohort, and the top known reason for discontinuation was the presence of side effects. However, many patients were taken off their AEDs for unknown reasons which need to be further investigated. Funding: No funding support was provided in support of this abstract.