Severity of Epilepsy and Response to Antiseizure Medications in Individuals With Multiple Sclerosis

Abstract

Background and ObjectivesEpilepsy is an important comorbidity that affects outcomes for people with multiple sclerosis (MS). However, it is unclear whether seizure severity among individuals with coexistence of MS and epilepsy (MS + E) is higher than in those with other focal epilepsies. Our goal was to compare the overall severity of epilepsy in individuals with MS + E vs those with focal epilepsy without MS (E − MS), as defined by seizure-related health care utilization, frequency and duration of status epilepticus, and frequency of antiseizure medication (ASM) regimen changes.MethodsIn this hypothesis-generating study, we analyzed a US commercial nationwide deidentified claims data set with >86 million individuals between January 1, 2008, and August 31, 2019. Using validated algorithms, we identified adults with E − MS and those with MS + E. We compared the number and length of seizure-related hospital admissions, the number of claims and unique days with claims for status epilepticus, and the rates of ASM regimen changes between the MS + E and E − MS groups.ResultsDuring the study period, 66,708 individuals with E − MS and 537 with MS + E had ≥2 years of coverage after their initial diagnosis of epilepsy. There was no difference between the MS + E and E − MS groups in the percentage of individuals admitted for seizures and/or status epilepticus. However, MS + E with seizure-related admissions had more admissions and longer hospital stays than those with E − MS. MS + E who experienced status epilepticus had more unique days with status epilepticus claims compared with E − MS. MS + E were more likely to have ASM regimen changes in 2 years after the initial diagnosis of epilepsy and had more ASM changes during 2 years compared with E − MS. Among individuals with MS + E, there were no differences in our measures of seizure severity for those treated with sodium channel blockers/modulators vs other ASM classes.DiscussionThis study supports the notion that individuals with MS + E can have more severe epilepsy than those with E − MS. Seizure severity among individuals with MS + E treated with sodium channel blockers/modulators vs other ASM classes shows no significant differences.Classification of EvidenceThis study provides Class III evidence that individuals with MS + E can have more severe epilepsy than those with E − MS.