Lamotrigine and Exogenous Estrogen Among Females with Epilepsy: An Analysis of Administrative Claims Data
Abstract number :
1.238
Submission category :
4. Clinical Epilepsy / 4E. Women's Issues
Year :
2023
Submission ID :
43
Source :
www.aesnet.org
Presentation date :
12/2/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Laura Kirkpatrick, MD – UPMC Children's Hospital of Pittsburgh
Samuel Terman, MD, MS – University of Michigan; Elizabeth Harrison, MD, MS – UPMC Children's Hospital of Pittsburgh; Page Pennell, MD – University of Pittsburgh
Rationale: Exogenous estrogen reduces lamotrigine levels. Experts recommend empirically increasing lamotrigine dose with addition of exogenous estrogen. However, it is unknown how often this recommendation is followed in clinical practice. The objective of this study was to determine the incidence of dose increases in lamotrigine following addition of exogenous estrogen among a cohort of U.S. females with epilepsy (FWE) in administrative claims data.
Methods: We used Optum’s de-identified Clinformatics® Data Mart Database to create a cohort of U.S. FWE of all ages prescribed lamotrigine at a stable dose, with a subsequent prescription for exogenous estrogen. We defined a stable dose as at least two lamotrigine prescriptions at least 60 days apart with no dose change between scripts, excluding lamotrigine starter packs. We required that individuals have at least one ICD code (counting Emergency Room, inpatient, and outpatient evaluation/management visits) for epilepsy (ICD-9: 345.xx; ICD-10: G40.XX), or at least two ICD codes for convulsions (ICD-9: 780.3X; ICD-10: R56.XX) at least 30 days apart, at any point simultaneous with or before the first date of their stably dosed lamotrigine prescription. We calculated a cumulative incidence function of dose increase in lamotrigine following prescription of exogenous prescription. We performed a Cox proportional hazards model for multiple candidate predictors of a lamotrigine dose increase.
Results: The cohort included 643 FWE. The median age was 31 (interquartile ratio [IQR] 20-42). The cumulative incidence of any lamotrigine increase was 28% (95% CI 25%-32%). The median number of days after the first estrogen fill until the first lamotrigine adjustment was 118 ([IQR] 48-188). Three FWE had an acute seizure visit on the same day as their first estrogen fill and thus contributed zero person-time of follow-up in our time-to-event analyses. Thus, for our Cox models, 640 FWE were available for analysis. In unadjusted Cox models, age, estrogen indication (hormone replacement therapy compared to contraception), and household income (for income of $50,000-99,9999 compared with income < $50,000) were significant predictors of lamotrigine dose increase (Table 1). In the adjusted Cox model, age and household income as above remained statistically significant predictors of lamotrigine dose increase (Table 2).
Clinical Epilepsy