Association of first antiseizure medication with acute health care utilization in a cohort of adults with newly diagnosed epilepsy

Objective: Epilepsy is primarily treated with antiseizure medications (ASMs). The recommendations for first ASM in newly diagnosed epilepsy are inconsistently followed, and we sought to examine whether nonrecommended first ASM was associated with acute care utilization. Methods: We conducted a retrospective cohort study of adults (>= 18 years old) with newly diagnosed epilepsy (identified using validated epilepsy/convulsion International Classification of Diseases, Clinical Modification codes) in 2015-2019, sampled from Marketscan's Commercial and Medicare Databases. Exposure of interest was receipt of a non-guideline-recommended ASM, and the primary outcome was acute care utilization (an emergency department visit or hospitalization after the first ASM claim). Descriptive statistics characterized covariates, and multivariable negative binominal regression models were built adjusting for age, sex, Elixhauser Comorbidity Index, comorbid neurologic disease (e.g., stroke), and ASM polypharmacy. Results: Approximately 14 681 people with new epilepsy were prescribed an ASM within 1 year. The three most prescribed medications were levetiracetam (54%, n = 7912), gabapentin (10%, n = 1462), and topiramate (7%, n = 1022). Approximately 4% (n = 648) were prescribed an ASM that should be avoided, and similar to 74% of people with new epilepsy had an acute care visit during the follow-up period. Mean number of acute care visits during follow-up was 3.34 for "recommended" ASMs and 4.42 for ASMs that "should be avoided." Prescription of a recommended/neutral ASM as compared to an ASM that should be avoided was associated with reduced likelihood of acute care utilization (incidence rate ratio [IRR] = .85, 95% confidence interval [CI] = .77-.94). The recommended/neutral category of ASMs was not statistically significantly associated with seizure- or epilepsy-specific acute care utilization (IRR = .93, 95% CI = .79-1.09). Significance: Adults with new epilepsy are frequent users of acute care. There remain a proportion of persons with epilepsy prescribed ASMs that guidelines suggest avoiding, and these ASMs are associated with increased likelihood of emergency department visit or hospitalization. These findings reinforce the importance of optimizing the choice of first ASM in epilepsy.