Authors :
Presenting Author: Christopher Zimmerman, DO – VA Northern California Healthcare System
Andrea Hildebrand, MS – VA Portland Healthcare System
Tia Dinatale, MPH – Salt Lake City VA HCS
Julie Lynch, PhD, RN, MBA – Salt Lake City VA HCS & Univ of Utah
Craig Teerlink, PhD – Salt Lake City VA HCS & Univ of Utah
Mary Jo Pugh, PhD, RN – VA Salt Lake City Healthcare System
Cecelia Madison, MS – VA Portland Healthcare System
Alica Goldman, MD, PhD – Baylor University
Nishant Mishra, MD, PhD – West Haven VA Medical Center
Marissa Kellogg, MD, PhD – VA Portland Healthcare System
Rationale: The VA’s Million Veteran Program (MVP) genetic research biobank has recruited over one million U.S. Veterans with the aim of understanding how lifestyle, genetics, and exposures affect health and wellness in Veterans. Participants provide consent and a DNA sample for genotyping, genome sequencing, methylation studies, and to link genetic data with their full federal electronic medical record (EMR). This study examines how anti-seizure medication (ASM) exposures in the full cohort (FC) compare with the subgroup with epilepsy.
This analysis represents an early phenotyping step in a larger study of the genetic epidemiology of epilepsy and pharmacogenomics in MVP.Methods: Medication prescription and pharmacy fill data were obtained to characterize ASM exposures and duration; extended duration (XD) was defined as more than 365 days. ASMs were categorized as epilepsy-specific medications (ESMs) if rarely used for indications other than epilepsy. The epilepsy subgroup (ES) was identified using a validated VA administrative algorithm that requires epilepsy-specific ICD codes be used concurrently with XD ASM. Descriptive statistics and figures were generated using Excel and R.
Results:
Of the 1,016,584 MVP participants in the FC (enrolled through 9/2024), 531,009 (52.2%) were prescribed one or more ASMs, of which 324,582 (31.9%) had XD. The ES group (n = 41,842) represents 4.1% of the FC, all of whom had XD ASM exposure. ESM exposure was higher in the ES than FC (52.7% vs 3.7%, p< 0.001). In the FC, the most common extended ASM exposures were gabapentin (22.9% of FC), clonazepam (3.6%), valproate (3.9%), topiramate (3.4%), pregabalin (3.3%), and lamotrigine (2.3%) (see Figure 1). In the ES, the most common extended ASMs exposures were gabapentin (54.9% of EG), levetiracetam (29.1%), valproate (24.6%), topiramate (15.5%), lamotrigine (15.1%), clonazepam (14.6%), and phenytoin (12.1%). Among participants who used XD ESM, 92.8% were in the ES (see Figure 2).