Etiology‐specific response to antiseizure medication in focal epilepsy

Abstract

Objective In focal epilepsy, data on the etiology‐specific response to antiseizure medication (ASM) are surprisingly sparse. In this study, we sought to reappraise whether seizure outcome of pharmacological treatment is linked to the underlying etiology. Furthermore, we assessed ASM load with respect to the cause of epilepsy. Methods Data were retrospectively obtained from the electronic database of the three sites of an academic adult epilepsy outpatient clinic. For each patient, presumed cause of epilepsy was categorized into one of nine etiological groups. Individual drug loads were calculated according to the 2020 World Health Organization Center for Drug Statistics Methodology ATC/DDD Index. Univariate and multivariate analyses were conducted to explore the association between different etiologies and outcome regarding 12‐month seizure freedom as well as ASM load. Results A total of 591 patients with focal epilepsy were included in the final analysis. Ischemic stroke was the etiology with the highest rate of 12‐month terminal seizure freedom (71.2%, 95% confidence interval [CI] = 57.9–82.2) and, considering all etiological groups, was an independent predictor of seizure freedom (odds ratio = 2.093, 95% CI = 1.039–4.216). The lowest rates of seizure freedom were observed in patients with hippocampal sclerosis (28.2%, 95% CI = 15.0–44.9) and malformation of cortical development (16.7%, 95% CI = 2.1–48.4). In patients with ischemic stroke, median ASM load (1.0, interquartile range [IQR] = .5–1.8) was significantly lower compared to that in patients with hippocampal sclerosis (median = 1.8, IQR = 1.2–3.0, p = .008) and brain tumors (median = 1.7, IQR = .7–3.2, p = .049). Significance Response to treatment with ASM is highly etiology‐specific and best in patients with epilepsy due to ischemic stroke. Interestingly, this most favorable treatment outcome can be achieved by the lowest ASM load considering all etiological groups. In focal epilepsy, etiology should be taken into account when counseling patients about their expected seizure outcome with pharmacological treatment and when tailoring initial ASM doses.

Non‐discontinuation of antiseizure medication in seizure‐free epilepsy patients

“…This might be interpreted as an expression of the benign course in our patient cohort. Previously published data from our outpatient clinics on patients with focal epilepsies, including those on polytherapy, also demonstrate similarly low values [18].…”

Big data analysis of ASM retention rates and expert ASM algorithm: A comparative study

“…A growing body of evidence hints at the complexity of selecting the optimal first ASM; multiple factors such as age, sex, comorbidities, and etiology seem to influence retention rates. 2,3 Several strategies exist to improve ASM success rates: algorithms providing expert opinion, studies providing randomized evidence, and big data. There are pros and cons of all these approaches.…”

“…The proportion of persons with epilepsy who remain on a suboptimal ASM and have seizures or side effects as a consequence is unknown. A growing body of evidence hints at the complexity of selecting the optimal first ASM; multiple factors such as age, sex, comorbidities, and etiology seem to influence retention rates 2,3 . Several strategies exist to improve ASM success rates: algorithms providing expert opinion, studies providing randomized evidence, and big data.…”

First seizure in elderly patients: Need to treat? Evidence from a retrospective study

“…Neither the effect of neuroimaging results nor of IED on the recurrence rates could be confirmed in the present study. The lack of an association between seizure recurrence and structural brain lesions in our patients might be related to the high incidence of ischemic stroke, as this etiology was associated with the highest percentage of long-term seizure freedom in patients with focal epilepsies of different etiologies [ 5 ]. Future research might focus on the distinct contributions of specific lesions to seizure recurrence more in depth.…”