Risk of breakthrough seizures depends on type and etiology of epilepsy.

OBJECTIVE: This study was undertaken to analyze whether the rate of breakthrough seizures in patients taking antiseizure medication (ASM) who have been seizure-free for at least 12 months varies among different types and etiologies of epilepsy. Given the relative ease of achieving seizure freedom with ASM in patients with post-ischemic stroke epilepsy, we hypothesized that this etiology is associated with a reduced risk of breakthrough seizures. METHODS: We defined a breakthrough seizure as an unprovoked seizure occurring while the patient was taking ASM after a period of at least 12 months without seizures. Data were analyzed retrospectively from a tertiary epilepsy outpatient clinic. Patients were eligible for inclusion if they either had a breakthrough seizure at any time or a seizure-free interval of at least 2 years. Our primary endpoint was rate of breakthrough seizures. We conducted univariable and multivariable analyses to identify variables associated with breakthrough seizures. RESULTS: Of 521 patients (53% females, median age = 49 years) included, 29% had a breakthrough seizure, which occurred after a median seizure-free interval of 34 months (quartiles = 22, 62). When controlling for clinically relevant covariates, breakthrough seizures were associated with post-ischemic stroke epilepsy (odds ratio [OR] = .267, 95% confidence interval [CI] = .075-.946), genetic generalized epilepsy (OR = .559; 95% CI = .319-.978), intellectual disability (OR = 2.768, 95% CI = 1.271-6.031), and the number of ASMs previously and currently tried (OR = 1.203, 95% CI = 1.056-1.371). Of the 151 patients with breakthrough seizures, 34.3% did not reachieve terminal 12-month seizure freedom at the last visit. SIGNIFICANCE: This is the first study to show an association between type and etiology of epilepsy and risk of breakthrough seizures. Our data suggest that epilepsies in which seizure freedom can be obtained more easily also exhibit a lower risk of breakthrough seizures. These findings may help to better counsel seizure-free patients on their further seizure prognosis.

Non-discontinuation of antiseizure medication in seizure-free epilepsy patients.

BACKGROUND AND PURPOSE: In patients with epilepsy and sustained seizure freedom, guidelines recommend considering discontinuation of antiseizure medication (ASM) based on shared decision-making. This study aims to identify factors associated with non-discontinuation of ASM in seizure-free patients. METHODS: Retrospective data from three sites of an academic outpatient clinic were analyzed. Adult patients with epilepsy who have been seizure-free for ≥24 months on ASM monotherapy were included. The primary end-point was non-discontinuation of ASM, defined as no discontinuation or no dose reduction of ≥25% at the last outpatient clinic visit in the ultimate seizure-free interval. Secondary end-points included frequency of discussion on discontinuation attempts between patients and physicians, adherence to ASM discontinuation decisions, and post-discontinuation seizure outcomes. RESULTS: Out of 338 included patients, 81.7% did not discontinue ASM and did not reduce its dose, 11.5% discontinued ASM and 6.8% had a significant dose reduction. Factors independently associated with non-discontinuation of ASM were history of focal to bilateral or generalized tonic-clonic seizures (odds ratio [OR] 2.33, 95% confidence interval [CI] 1.08-5.06), history of breakthrough seizures (OR 3.32, 95% CI 1.10-10.04), history of failed attempts to discontinue or reduce the ASM dose (OR 4.67, 95% CI 1.03-21.11) and higher ASM load at the index visit (OR 6.10, 95% CI 2.09-17.78). Discontinuation attempts were made during the entire period of seizure freedom and were most commonly undertaken ≥10 years after the last seizure. CONCLUSIONS: This study provides insights into factors associated with the shared decision-making process regarding ASM discontinuation in seizure-free patients and highlights the importance of considering individual patient characteristics and seizure history.

[Discontinuation of antiseizure medication in patients with epilepsy]. / Absetzen anfallssuppressiver Medikamente bei Patient*innen mit Epilepsie.

BACKGROUND: Approximately two thirds of patients with epilepsy become seizure-free with antiseizure medication (ASM). A central question is whether and when ASM can be discontinued. OBJECTIVE: To present an overview of the current knowledge about risks and benefits of discontinuation of ASM. MATERIAL AND METHODS: Review of the current literature, discussion of data on and recommendations for discontinuation of ASM. RESULTS: The risk of seizure recurrence after discontinuation of ASM is approximately 40-50% and thus twice as high as continuing with ASM. Guidelines recommend considering discontinuation of ASM at earliest after a seizure-free period of 2 years. Predictive variables for seizure recurrence after stopping ASM include longer duration of epilepsy and higher number of seizures until remission, a shorter seizure-free interval until stopping ASM, older age at epilepsy onset, developmental delay or IQ < 70, febrile seizures in childhood, absence of a self-limiting epilepsy syndrome, and evidence of epileptiform activity in the electroencephalograph (EEG). The individual risk of seizure recurrence after stopping ASM can be estimated using an online prediction tool. CONCLUSION: Discontinuation of ASM should be discussed with patients at the earliest after 2 years of seizure freedom in a shared decision-making process weighing up the risks and benefits. The risk of a seizure recurrence depends on a number of clinical variables. Psychosocial aspects, such as impact on driving and occupational issues must be taken into consideration as well as individual fears and concerns of patients about seizure recurrence or the long-term use of ASM.