Prognosis after withdrawal of antiepileptic drugs in childhood-onset cryptogenic localization-related epilepsies

Mapping the methodological diversity of published drug discontinuation studies-a scoping review of study topics, objectives, and designs

BACKGROUND

Trials evaluating drug discontinuation (drug discontinuation trials, DDTs) show a broad methodological spectrum. There are several specific methodological aspects in drug discontinuation trials (e.g., determination of research question; configuration of intervention; definition of outcomes). To verify this specifies, we did a scoping review about the study designs of drug discontinuation trials.

METHODS

A systematic literature search in Medline (PubMed), The Cochrane Library, EMBASE, CINAHL, Web of Science, and PsycINFO was performed. In a two-step selection process, we identified DDTs, which evaluate the discontinuation of one or more long-term medication as the investigated intervention, by two independent reviewers. Besides bibliographic data, we extracted several parameters to describe the used study design of the included DDTs: motivation for DDT, initially treatment aim of the discontinued medication, study design, methods of discontinuation, follow-up times, number of study participants, and outcome parameter.

RESULTS

Out of 12,132 records, we included 581 DDTs. The most common motivation for doing a DDT were expected side effects (48.8%), the motivation of proving the efficacy of medication (21.6%), or doubts on the expected benefit of the used medication (13.8%). The majority of the discontinued medication was initially prescribed to improve the prognosis of a chronic disease (60.4%) or to relieve symptoms (31%). The study designs of the trials showed a broad methodological spectrum. The minority of the drug discontinuation trials were randomized controlled trials (34%).

CONCLUSION

The results of this scoping review illustrates the need for an evidence-based methodological standard for planning and conducting drug discontinuation trials.

Risk factors of recurrence after drug withdrawal in children with epilepsy

This study aimed to evaluate the risk factors for recurrence in pediatric patients with epilepsy following normal antiseizure medication (ASM) treatment and drug withdrawal. We retrospectively analyzed 80 pediatric patients who received treatment at the Qilu Hospital of Shandong University between January 2009 and December 2019 after at least 2 years of seizure-free and normal electroencephalography (EEG) before the regular drug reduction. Patients were followed-up for at least 2 years and divided into the recurrence and nonrecurrence groups based on whether relapse occurred. Clinical information was gathered, and the risk variables for recurrence were statistically analyzed. Post 2 years of drug withdrawal, 19 patients showed relapses. The recurrence rate was 23.75%, and the mean time of recurrence was 11.09 ± 7.57 months, where 7 (36.8%) were women and 12 (63.2%) were men. In all, 41 pediatric patients were followed-up until the 3rd year, of which 2 (4.9%) patients experienced a relapse. Among the remaining 39 patients without relapse, 24 were followed-up until the 4th year, and no recurrence occurred. After being monitored for >4 years, 13 patients experienced no recurrence. The differences in the history of febrile seizures, combined use of ≥2 ASMs, and EEG abnormalities after drug withdrawal between the two groups were statistically significant (p < 0.05). Multivariate binary logistic regression analysis revealed that these factors are independent risk factors for recurrence after drug withdrawal in children with epilepsy: history of febrile seizures (OR = 4.322, 95% CI: 1.262-14.804), combined ASM use (OR = 4.783, 95% CI: 1.409-16.238), and EEG abnormalities after drug withdrawal (OR = 4.688, 95% CI: 1.154-19.050). In summary, our results suggest that the probability of seizure recurrence following drug cessation may be greatly increased by a history of febrile seizures, concomitant use of ≥2 ASMs, and EEG abnormalities after drug cessation. The majority of recurrences occurred in the first 2 years following drug discontinuation, whereas the rate of recurrence was minimal thereafter.

Risk of seizure relapse and long-term outcomes after discontinuation of antiseizure medication in children with epilepsy

OBJECTIVES

The aims of this study were to evaluate the demographic and clinical characteristics of children with epilepsy who discontinued their antiseizure medication (ASM), to determine potential predictors of seizure relapse, to calculate the rate of seizure relapse, and to detect long-term seizure outcomes.

METHODS

A total of 269 seizure-free children with epilepsy who were decided to discontinue their ASM and were followed up for at least 18 months after ASM withdrawal were retrospectively evaluated.

RESULTS

The enrolled children had been followed up for a median of 46 months (range 18-126 months; IQR: 29-61) after ASM withdrawal and 90 (33.5%) of their seizures relapsed. The median time to seizure relapse was 8 months (range 0.23-117 months; IQR: 2-25). Seizure relapse occurred in 16.7% of the 90 children at 1 month, 45.6% at 6 months, 62.2% at 1 year, 74.4% at 2 years, and 94.4% at 5 years. Univariate logistic regression analyses revealed six predictors significantly related to relapse: age at first seizure, age at diagnosis of epilepsy, intellectual disability, EEG findings after ASM withdrawal, ASM tapering time, and number of seizures on ASM. In multivariate logistic regression analyses, age at first seizure, intellectual disability, and ASM tapering time were not significantly associated anymore. The other three remained independently predictive. Pharmacological control of seizures with monotherapy was restored in 93.3% of the children with seizure relapse.

CONCLUSION

This study evaluated potential predictors of seizure relapse, some of which have rarely been evaluated in previous studies. Adolescent age at diagnosis, abnormal EEG findings after ASM withdrawal, and high number of seizures on ASM were associated with a higher risk of seizure relapse. Abnormal MRI findings such as malformations of cortical development and hydrocephalus may be potential biomarkers for the risk of seizure relapse.

Risk of seizure recurrence from antiepileptic drug withdrawal among seizure-free patients for more than two years

OBJECTIVE

The aim of this study was to determine the outcome of antiepileptic drug (AED) withdrawal in patients who were seizure-free for more than two years.

METHODS

Patients with epilepsy who were seizure-free for at least two years and decided to stop AED therapy gradually were followed up every two months for seizure relapse. The inclusion criteria were as follows: (1) diagnosis of epilepsy, defined as the following conditions: ① at least two unprovoked (or reflex) seizures occurring >24 h apart; ② one unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years; ③ diagnosis of an epilepsy syndrome; (2) patients remained seizure-free for at least 24 consecutive months during AED therapy; and (3) patients expressed a desire to discontinue AED therapy gradually and agreed to return for regular follow-ups. The time to a seizure relapse and predictive factors were analyzed by survival methods, including sex; age at seizure onset; number of episodes; seizure-free period before AED withdrawal; duration of follow-up after AED withdrawal; AED tapering off period (taper period); results from brain magnetic resonance (MRI); electroencephalogram (EEG) after drug withdrawal; EEG before drug withdrawal; seizure type (classified as generalized, partial, or multiple types based on history); and the number of AEDs administered for long-term seizure control. A log-rank test was used for univariate analysis, and a Cox proportional hazard model was used for multivariate analysis.

RESULTS

We selected 94 patients (58 men, 36 women). The relapse ratio was 29.8%. Univariate analysis and multivariate Cox regression analysis indicated that withdrawal times and multiple AEDs, as well as the seizure-free period before withdrawal and abnormal EEG after drug withdrawal were significantly correlated with seizure recurrence and were significant independent predictive factors, with a hazard ratio of 0.839 and 3.971, 0.957, and 3.684, respectively.

SIGNIFICANCE

The relapse rate in our study was similar to commonly reported overall rates for epilepsy. Distinguishing variables, such as withdrawal times, multiple AEDs, seizure-free period before withdrawal, and abnormal EEG after drug withdrawal, need to be considered when choosing to withdraw from AEDs. Therefore, our recommendation is that after two years of seizure-free survival, patients could consider withdrawal unless they have hippocampal sclerosis (HS).

Prediction of the recurrence risk in patients with epilepsy after the withdrawal of antiepileptic drugs

Many seizure-free patients who consider withdrawing from antiepileptic drugs (AEDs) hope to discontinue treatment to avoid adverse effects. However, withdrawal has certain risks that are difficult to predict. In this study, we performed a literature review, summarized the causes of significant variability in the risk of postwithdrawal recurrent seizures, and reviewed study data on the age at onset, cause, types of seizures, epilepsy syndrome, magnetic resonance imaging (MRI) abnormalities, epilepsy surgery, and withdrawal outcomes of patients with epilepsy. Many factors are associated with recurrent seizures after AED withdrawal. For patients who are seizure-free after treatment, the role of an electroencephalogram (EEG) alone in ensuring safe withdrawal is limited. A series of prediction models for the postwithdrawal recurrence risk have incorporated various potentially important factors in a comprehensive analysis. We focused on the populations of studies investigating five risk prediction models and analyzed the predictive variables and recommended applications of each model, aiming to provide a reference for personalized withdrawal for patients with epilepsy in clinical practice.

Relative Seizure Relapse Risks Associated with Antiepileptic Drug Withdrawal After Different Seizure-Free Periods in Adults with Focal Epilepsy: A Prospective, Controlled Follow-Up Study

BACKGROUND

Approximately two-thirds of patients with newly diagnosed epilepsy become seizure-free after antiepileptic drug (AED) treatment. A crucial issue for these patients and their families, especially after a long period of seizure freedom, is when to stop their medications.

OBJECTIVE

The aim of this study was to identify the optimal timing of AED withdrawal in adults with focal epilepsy who had been seizure-free for ≥ 2 years.

METHODS

Adults with focal epilepsy who had been seizure-free for ≥ 2 years were recruited. Based on their decision to discontinue (withdrawal) or continue (non-withdrawal) AED treatment, patients were assigned to withdrawal or non-withdrawal subgroups according to the length of remission (2 to < 3 years, 3 to < 4 years, 4 to < 5 years and ≥ 5 years). The relapse risks of the withdrawal and corresponding non-withdrawal subgroups were compared, and the relative relapse risks were assessed in a Cox proportional hazard regression model.

RESULTS

A total of 213 eligible patients began to withdraw from AED treatment; 70 had been seizure-free for 2 to < 3 years, 62 had been seizure-free for 3 to < 4 years, 37 had been seizure-free for 4 to < 5 years and 44 had been seizure-free for ≥ 5 years. The figures for the corresponding non-withdrawal subgroups were 463, 334, 251 and 182, respectively. There was a significantly higher risk of seizure relapse in patients withdrawing from AEDs after 2 to < 5 years of seizure freedom than in the corresponding non-withdrawal controls, and the relative relapse risk was 3.052 (95% confidence interval [CI] 2.126-4.381; p < 0.001) for the seizure-free period of 2 to < 3 years, 3.617 (95% CI 2.384-5.488; p < 0.001) for 3 to < 4 years and 2.644 (95% CI 1.456-4.799; p = 0.001) for 4 to < 5 years. However, for patients who were seizure-free for ≥ 5 years, AED withdrawal did not significantly increase the risk of seizure relapse compared with that of patients continuing treatment (hazard ratio [HR] 1.362, 95% CI 0.634-2.926, p = 0.428). Compared with a seizure-free period of 2 to < 3 years, the relative relapse risk after AED withdrawal was significantly reduced only after being seizure-free for ≥ 5 years (HR 0.441, 95% CI 0.233-0.834; p = 0.012).

CONCLUSION

Overall, for adults with focal epilepsy, withdrawal from AEDs significantly increased the risk of seizure relapse after being seizure-free for 2 to < 5 years, but might not increase the risk if the seizure-free period was ≥ 5 years.

Uncertainties from a worldwide survey on antiepileptic drug withdrawal after seizure remission

Background

We sought to determine differences in practice for discontinuation of antiepileptic drugs (AEDs) after seizure remission and stimulate the planning and conduction of withdrawal trials.

Methods

We utilized a worldwide electronic survey that included questions about AED discontinuation for 3 paradigmatic cases in remission: (1) focal epilepsy of unknown etiology, (2) temporal lobe epilepsy after surgery, and (3) juvenile myoclonic epilepsy. We analyzed 466 complete questionnaires from 53 countries, including the United States. Statistical analysis included χ² and multivariate logistic regression.

Results

Case 1: responders in practice for <10 years were less likely to taper AEDs: odds ratio (OR) (95% confidence interval [CI]) 0.52 (0.32-0.85), p = 0.02. The likelihood of stopping AEDs was higher among doctors treating children: OR (95% CI): 11.41 (2.51-40.13), p = 0.002. Doctors treating children were also more likely to stop after 2 years or less of remission: OR (95% CI): 6.91 (2.62-19.31), p = 0.002, and the same was observed for US physicians: OR (95% CI): 1.61 (1.01-2.57), p = 0.0049. Case 2: responders treating children were more likely to taper after 1 year or less of postoperative remission, with the goal of discontinuing all medications: OR (95% CI): 1.91 (1.09-3.12), p = 0.015, and so were US-based responders: OR (95% CI): 1.73 (1.21-2.41), p = 0.003. Case 3: epileptologists were less likely to withdraw the medication: OR (95% CI): 0.56 (0.39-0.82), p = 0.003, and so were those in practice for 10 or more years: OR (95% CI): 0.54 (0.31-0.95), p = 0.025.

Conclusions

We observed several differences in practice for AED withdrawal after seizure remission that highlight global uncertainty. Trials of AED discontinuation are needed to provide evidence-based guidance.

Prospective study on the withdrawal and reinstitution of antiepileptic drugs among seizure-free patients in west China

This study explored the relapse rates and risk factors for seizure recurrence after discontinuing antiepileptic drug (AED) therapy among seizure-free patients in west China, and explored whether to reinstitute AED immediately after a single seizure after AED withdrawal. Patients with epilepsy who were seizure-free for at least 2 years and decided to gradually stop AED therapy were followed up every 3 months for seizure relapse. Patients who experienced their first seizure after drug withdrawal were divided into two groups according to their willingness to reinstitute AED therapy, and were followed up until their second seizure. In the mean 29.35 months of follow-up, 37 patients (37/162, 22.8%) suffered at least one seizure after withdrawal. The cumulative probability of seizure recurrence was 16% at 12 months and 20.2% at 24 months. AED response time >1 year and multiple types of seizure were identified as risk factors for seizure recurrence. Eight patients (8/32, 25%) suffered a second seizure within 1 year after the first whether or not they reinstituted AED immediately. There were no significant demographic or clinical differences between patients who reinstituted AED therapy and those who did not. The epilepsy recurrence rate after AED withdrawal is relatively low, with a relatively slow tapering process. Patients with long AED response times and/or multiple types of seizures have a higher risk of seizure recurrence. The first seizure after drug withdrawal is not an indication for immediate AED reinstitution, but may be recommended after a second seizure.

Predictors for relapse after antiepileptic drug withdrawal in seizure-free patients with epilepsy

The objective of this study was to evaluate the timing of medication withdrawal and other clinical factors as potential predictors of seizure relapse after antiepileptic drug (AED) withdrawal in patients with epilepsy. A total of 99 patients who were seizure free for more than 2 years were recruited from the Neurology Clinics of Nanjing Brain Hospital between 2001 and 2009, and were followed prospectively for at least 2 years or until seizure relapse. Kaplan-Meier survival analysis was used for calculating recurrence rates. Univariate and multivariate analyses for recurrence risk factors were performed using the Cox proportional hazards model. Thirteen patients were excluded due to loss of follow-up or incomplete seizure records. Epileptiform electroencephalography (EEG) abnormality within the first year after AED withdrawal (hazard ratio [HR] = 4.810, 95% confidence interval [CI] = 2.220-10.420) was found on multivariate analysis to be a predictor of seizure recurrence. Early AED withdrawal after a seizure-free period of 2-3 years did not significantly increase the risk of recurrence (HR = 0.999, 95% CI = 0.969-1.029) as compared with delayed AED withdrawal (patients who were seizure-free for more than 3 years). AED can be withdrawn in patients who have been seizure-free for more than 2 years. As epileptiform EEG abnormality within the first year after AED withdrawal predicts seizure relapse, it is necessary to perform EEG for patients during the first year after AED withdrawal.

Determination of risk factors associated with seizure relapse after antiepileptic drug withdrawal

There is no consensus regarding the time of antiepileptic drug withdrawal and the relevant risk factors for seizure relapse. In this study, we aimed to determine the seizure relapse rates and the associated risk factors for seizure relapse in childhood epilepsy. Two-hundred sixty-six epileptic patients who discontinued the antiepileptic drug therapy after a seizure-free period of at least two years, were enrolled into the study. The data of the patients regarding sex, febrile convulsion history, family history, age at onset, type of epilepsy, total number of seizures and antiepileptic drugs, seizures during treatment, mental status, first and last electroencephalography, brain imaging findings, etiological factors and seizure relapse in the first two years after antiepileptic drug withdrawal were obtained from the patients’ files. Univariate logistic regression analysis was performed for each variable. The variables which were found to be statistically significant in univariate analysis, were included in multivariate logistic regression analysis. The overall seizure relapse rate after antiepileptic drug withdrawal was 19.2%. There were no significant differences for seizure relapse rate after antiepileptic drug withdrawal between patient groups with respect to sex, family history, type of epilepsy, febrile convulsion history, seizures before treatment, first electroencephalography findings, brain imaging findings and etiology. However, there were statistically significant differences for seizure relapse rate among patient groups concerning age at onset of epilepsy, new seizure during treatment, the total number of antiepileptic drugs, mental status, and last electroencephalography findings. We imply that the clinical status of the patients should be considered before the cessation of drug therapy rather than the etiological factors or laboratory findings.

Recurrence risk after withdrawal of antiepileptic drugs in children with epilepsy: a prospective study

AIM

To study recurrence risk after withdrawal of antiepileptic drugs in children with epilepsy.

METHODS

All children younger than 14 with two or more unprovoked seizures 24h apart who were seen at our Hospital between 1994 and 2004 were included consecutively and prospectively followed. Patients previously examined in other centres were excluded. All patients who entered a remission were proposed to stop medication and were followed.

RESULTS

Three hundred and fifty three children with two or more unprovoked seizures were attended. A total of 238 entered a remission period and were proposed to stop medication, 216 accept. Mean seizure-free time before medication withdrawal was 2.2 years. Kaplan-Meier estimate of recurrence risk was 23% at 2 years (95% CI: 17-29) and 28% at 5 years (95% CI: 22-34). A remote symptomatic etiology, various seizure types and a history of prior febrile seizures or prior neonatal seizures were associated with a significant increase in recurrence risk in univariable and multivariable analyses using Cox proportional hazards model. Recurrence risk at 2 years was 17% (95% CI: 11-23) for idiopathic/cryptogenic epilepsies and 41% (85% CI: 28-54) for remote symptomatic epilepsies. Recurrence risks at 2 years by epileptic syndrome were West syndrome (0%), benign rolandic epilepsy (10%), epilepsy without unequivocal partial or generalized seizures (11%), benign infantile seizures (13%), absence epilepsy (16%), cryptogenic partial epilepsies (20%), symptomatic partial epilepsies (45%), symptomatic generalized epilepsies (54%).

CONCLUSIONS

Recurrence risk after withdrawal of antiepileptic treatment in children is low. Etiology and syndromic diagnosis are the main predictive factors.

A systematic review of antiepileptic drug initiation and withdrawal

BACKGROUND

The proper clinical context to initiate or discontinue antiepileptic drug (AED) treatment has been extensively studied over the past 40 years. Differences in study design and methodology have led to reports of seizure recurrence rates of 7% to 96% in drug initiation trials and seizure relapse rates of 12% to 67% in drug withdrawal trials. A number of different historical and clinical factors have been cited in various studies as altering seizure risk. Our objective was to review the data from large, well-conducted, prospective studies.

REVIEW SUMMARY

We performed an electronic search of 3 medical and scientific databases for articles on initiating or withdrawing antiepileptic medication. Our review focused primarily on articles meeting specific inclusion and exclusion criteria. We discuss the risk of seizure recurrence after a first seizure and the factors associated with an elevated risk of recurrence. The risks of treatment, including life-threatening idiosyncratic reactions and dose-related physical and cognitive side effects are reviewed. We also summarize the data on the seizure relapse risk after drug discontinuation and the factors associated with an increased relapse risk. Benefits of successful AED withdrawal are highlighted. The special considerations of treatment initiation and withdrawal in the pediatric population are explored. We propose general guidelines to assist the clinician in evaluating the risk/benefit ratio of initiating and withdrawing antiepileptic drugs.

CONCLUSION

Drug initiation after a first seizure decreases early seizure recurrence, but does not affect the long-term prognosis of developing epilepsy. Medication withdrawal after a period of seizure remission increases the risk of relapse, but the benefits of successful AED discontinuation may be substantial. In the end, the decision of whether to initiate treatment after a single seizure and whether to withdraw AED therapy in patients enjoying a prolonged period of seizure freedom should be made on an individual case basis, which balances the risk of seizure relapse and subsequent disability against the likely impact of medication-related physical, cognitive, and psychologic adverse effects.

The validity of a separate classification of cryptogenic localization related epilepsy amongst childhood epilepsies

INTRODUCTION

One-third of children with epilepsy are classified as having a cryptogenic localization related epilepsy (CLRE). In cohort studies CLRE is often grouped together with either symptomatic localization related epilepsy (SLRE) or idiopathic generalized epilepsy (IGE). Therefore, this categorization is not specific enough and will not lead to prognostic or treatment information. We objectified the classification differences between these categories.

METHODS

A total of 114 children admitted to our epilepsy centre underwent a standardized clinical analysis, which yielded age at onset, duration of the epilepsy, seizure frequency, seizure type, percentage of interictal epileptiform activity on EEG (IEA), type of treatment, and full scale IQ. These variables are regarded the characteristics of the epilepsy, and used in a discriminant function analysis.

RESULTS

IEA was found to be the only variable to distinguish between groups of epilepsy. SLRE could easily be distinguished significantly from IGE and CLRE, while the latter two did not differ significantly. Discriminant function analysis combined the variables into two functions, applicable to classify the children. By applying this statistical analysis method, the groups clinically classified as SLRE and IGE were mostly classified as SLRE (71.4%) and IGE (57.9%). However, CLRE appeared difficult to classify (49.2%), and most children were classified as either SLRE (19%) or IGE (31.7%).

CONCLUSION

The current opinion that CLRE is 'probably symptomatic' cannot be confirmed in all cases in this study. It is most likely that the current CLRE population consists of both children with eventually SLRE, as well as yet to be described syndromes to be classified as idiopathic epilepsies. We emphasize the need for separate studies regarding children with 'probably symptomatic' (cryptogenic) localization related epilepsy, as this will maximally help children, caretakers and treating physicians to achieve the best possible outcome.

Cryptogenic localization-related epilepsy with childhood onset: The problem of definition and prognosis

BACKGROUND

Up to one-third of children with epilepsy are diagnosed with cryptogenic localization-related epilepsy (CLRE). CLRE is a large nonspecific category within the ILAE classification. For this population no unequivocal prognosis exists.

METHODS

Twenty-five articles describing aspects of CLRE were included in this review.

RESULTS

As a result of the progress in epilepsy research, as well as more advanced investigation in individual cases, the population with CLRE constantly changes. Also, disagreement on interpretation of the classification has resulted in striking differences between the populations described. High remission rates are reported, but relapse occurs frequently, leaving the long-term prognosis unforeseeable. This is reflected in academic and psychosocial prognosis, which is described to be problematic in CLRE specifically. Possible prognostic factors of CLRE in children have been identified: age at onset, seizure semiology, seizure frequency, intractability, interictal epileptiform activity on EEG, and premorbid IQ. These factors are explored to define subgroups within the CLRE population.

DISCUSSION

Prospective studies on well-defined CLRE cohorts are needed to identify factors that distinguish various prognostic subgroups. Specific attention should be focused on course of the epilepsy, scholastic achievement, and psychosocial outcome.