Assessment of treatment patterns and healthcare costs associated with probable Lennox-Gastaut syndrome

A comprehensive systematic literature review of the burden of illness of Lennox-Gastaut syndrome on patients, caregivers, and society

Fully elucidating the burden that Lennox-Gastaut syndrome (LGS) places on individuals with the disease and their caregivers is critical to improving outcomes and quality of life (QoL). This systematic literature review evaluated the global burden of illness of LGS, including clinical symptom burden, care requirements, QoL, comorbidities, caregiver burden, economic burden, and treatment burden (PROSPERO ID: CRD42022317413). MEDLINE, Embase, and the Cochrane Library were searched for articles that met predetermined criteria. After screening 1442 deduplicated articles and supplementary manual searches, 113 articles were included for review. A high clinical symptom burden of LGS was identified, with high seizure frequency and nonseizure symptoms (including developmental delay and intellectual disability) leading to low QoL and substantial care requirements for individuals with LGS, with the latter including daily function assistance for mobility, eating, and toileting. Multiple comorbidities were identified, with intellectual disorders having the highest prevalence. Although based on few studies, a high caregiver burden was also identified, which was associated with physical problems (including fatigue and sleep disturbances), social isolation, poor mental health, and financial difficulties. Most economic analyses focused on the high direct costs of LGS, which arose predominantly from medically treated seizure events, inpatient costs, and medication requirements. Pharmacoresistance was common, and many individuals required polytherapy and treatment changes over time. Few studies focused on the humanistic burden. Quality concerns were noted for sample representativeness, disease and outcome measures, and reporting clarity. In summary, a high burden of LGS on individuals, caregivers, and health care systems was identified, which may be alleviated by reducing the clinical symptom burden. These findings highlight the need for a greater understanding of and better definitions for the broad spectrum of LGS symptoms and development of treatments to alleviate nonseizure symptoms.

A systematic literature review on the global epidemiology of Dravet syndrome and Lennox-Gastaut syndrome: Prevalence, incidence, diagnosis, and mortality

Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) are rare developmental and epileptic encephalopathies associated with seizure and nonseizure symptoms. A comprehensive understanding of how many individuals are affected globally, the diagnostic journey they face, and the extent of mortality associated with these conditions is lacking. Here, we summarize and evaluate published data on the epidemiology of DS and LGS in terms of prevalence, incidence, diagnosis, genetic mutations, and mortality and sudden unexpected death in epilepsy (SUDEP) rates. The full study protocol is registered on PROSPERO (CRD42022316930). After screening 2172 deduplicated records, 91 unique records were included; 67 provided data on DS only, 17 provided data on LGS only, and seven provided data on both. Case definitions varied considerably across studies, particularly for LGS. Incidence and prevalence estimates per 100 000 individuals were generally higher for LGS than for DS (LGS: incidence proportion = 14.5-28, prevalence = 5.8-60.8; DS: incidence proportion = 2.2-6.5, prevalence = 1.2-6.5). Diagnostic delay was frequently reported for LGS, with a wider age range at diagnosis reported than for DS (DS, 1.6-9.2 years; LGS, 2-15 years). Genetic screening data were reported by 63 studies; all screened for SCN1A variants, and only one study specifically focused on individuals with LGS. Individuals with DS had a higher mortality estimate per 1000 person-years than individuals with LGS (DS, 15.84; LGS, 6.12) and a lower median age at death. SUDEP was the most frequently reported cause of death for individuals with DS. Only four studies reported mortality information for LGS, none of which included SUDEP. This systematic review highlights the paucity of epidemiological data available for DS and especially LGS, demonstrating the need for further research and adoption of standardized diagnostic criteria.

Interrater reliability of interictal EEG waveforms in Lennox-Gastaut Syndrome

OBJECTIVE

Identification of EEG waveforms is critical for diagnosing Lennox-Gastaut Syndrome (LGS) but is complicated by the progressive nature of the disease. Here, we assess the interrater reliability (IRR) among pediatric epileptologists for classifying EEG waveforms associated with LGS.

METHODS

A novel automated algorithm was used to objectively identify epochs of EEG with transient high power, which were termed events of interest (EOIs). The algorithm was applied to EEG from 20 LGS subjects and 20 healthy controls during NREM sleep, and 1350 EOIs were identified. Three raters independently reviewed the EOIs within isolated 15-second EEG segments in a randomized, blinded fashion. For each EOI, the raters assigned a waveform label (spike and slow wave, generalized paroxysmal fast activity, seizure, spindle, vertex, muscle, artifact, nothing, or other) and indicated the perceived subject type (LGS or control).

RESULTS

Labeling of subject type had 85% accuracy across all EOIs and an IRR of κ =0.790, suggesting that brief segments of EEG containing high-power waveforms can be reliably classified as pathological or normal. Waveform labels were less consistent, with κ =0.558, and the results were highly variable for different categories of waveforms. Label mismatches typically occurred when one reviewer selected "nothing," suggesting that reviewers had different thresholds for applying named labels.

SIGNIFICANCE

Classification of EEG waveforms associated with LGS has weak IRR, due in part to varying thresholds applied during visual review. Computational methods to objectively define EEG biomarkers of LGS may improve IRR and aid clinical decision-making.

Proposed anti-seizure medication combinations with rufinamide in the treatment of Lennox-Gastaut syndrome: Narrative review and expert opinion

Lennox-Gastaut syndrome (LGS) is a severe, chronic, complex form of early childhood-onset epilepsy characterized by multiple seizure types, generalized slow (≤2.5 Hz) spike-and-wave activity and other electroencephalography abnormalities, and cognitive impairment. A key treatment goal is early seizure control, and several anti-seizure medications (ASMs) are available. Due to the low success rate in achieving seizure control with monotherapy and an absence of efficacy data supporting any particular combination of ASMs for treating LGS, a rational approach to selection of appropriate polytherapy should be applied to maximize benefit to patients. Such "rational polytherapy" involves consideration of factors including safety (including boxed warnings), potential drug-drug interactions, and complementary mechanisms of action. Based on the authors' clinical experience, rufinamide offers a well-considered first adjunctive therapy for LGS, particularly in combination with clobazam and other newer agents for LGS, and may be particularly useful for reducing the frequency of tonic-atonic seizures associated with LGS.

The burden of illness in Lennox-Gastaut syndrome: a systematic literature review

BACKGROUND

Lennox-Gastaut syndrome (LGS) is a severe developmental and epileptic encephalopathy characterized by drug-resistant epilepsy with multiple seizure types starting in childhood, a typical slow spike-wave pattern on electroencephalogram, and cognitive dysfunction.

METHODS

We performed a systematic literature review according to the PRISMA guidelines to identify, synthesize and appraise the burden of illness in LGS (including "probable" LGS). Studies were identified by searching MEDLINE, Embase and APA PsychInfo, Cochrane's database of systematic reviews, and Epistemonikos. The outcomes were epidemiology (incidence, prevalence or mortality), direct and indirect costs, healthcare resource utilization, and patient and caregiver health-related quality of life (HRQoL).

RESULTS

The search identified 22 publications evaluating the epidemiology (n = 10), direct costs and resource (n = 10) and/or HRQoL (n = 5). No studies reporting on indirect costs were identified. With no specific ICD code for LGS in many regions, several studies had to rely upon indirect methods to identify their patient populations (e.g., algorithms to search insurance claims databases to identify "probable" LGS). There was heterogeneity between studies in how LGS was defined, the size of the populations, ages of the patients and length of the follow-up period. The prevalence varied from 4.2 to 60.8 per 100,000 people across studies for probable LGS and 2.9-28 per 100,000 for a confirmed/narrow definition of LGS. LGS was associated with high mortality rates compared to the general population and epilepsy population. Healthcare resource utilization and direct costs were substantial across all studies. Mean annual direct costs per person varied from $24,048 to $80,545 across studies, and home-based care and inpatient care were significant cost drivers. Studies showed that the HRQoL of patients and caregivers was adversely affected, although only a few studies were identified. In addition, studies suggested that seizure events were associated with higher costs and worse HRQoL. The risk of bias was low or moderate in most studies.

CONCLUSIONS

LGS is associated with a significant burden of illness featuring resistant seizures associated with higher costs and worse HRQoL. More research is needed, especially in evaluating indirect costs and caregiver burden, where there is a notable lack of studies.

Epidemiology, healthcare resource use, and mortality in patients with probable Dravet syndrome: A population-based study on German health insurance data

OBJECTIVE

Ten-year retrospective study to assess burden of illness in patients with probable Dravet syndrome (DS) identified from German healthcare data.

METHODS

In the absence of an International Classification of Diseases code, patients with probable DS were identified using a selection algorithm considering diagnoses and drug prescriptions. Primary analyses were prevalence and demographics; secondary analyses included healthcare costs, annual hospitalization rate (AHR) and length of stay (LOS), medication use, and mortality.

RESULTS

In the final study year, 64 patients with probable DS (mean [range] age: 33.2 [3-82] years; male: 48%) were identified. Prevalence: 4.7 per 100,000 people. During the study, 160 patients with probable DS were identified and followed up for 1,261 patient-years. Mean cost of healthcare was €11,048 per patient-year (PPY), mostly attributable to inpatient care (47%), medication (26%), and services and devices (19%). Annual healthcare costs were significantly greater for those with prescribed rescue medication (15% of patient-years) vs. without (€16,123 vs. €10,125 PPY, p < 0.001). Mean (standard deviation [SD]) AHR and LOS were 1.1 (1.7) and 17.5 (33.5) days PPY. AHR was significantly greater in patients with prescribed rescue medication vs. without (1.6 [2.0] vs. 1.0 [1.6] PPY, p < 0.001). Mean (SD) number of antiseizure medications prescribed was 2.6 (1.2) PPY and 5.0 (2.5) over the entire observable time for each patient. Mortality rate was significantly higher for probable DS vs. matched controls (11.88% [19 events] vs. 1.19% [172 events], p < 0.001).

CONCLUSION

Probable DS is associated with substantial healthcare costs in Germany.

Development and Evaluation of Computable Phenotypes in Pediatric Epilepsy:3 Cases

INTRODUCTION

Computable phenotypes allow identification of well-defined patient cohorts from electronic health record data. Little is known about the accuracy of diagnostic codes for important clinical concepts in pediatric epilepsy, such as (1) risk factors like neonatal hypoxic-ischemic encephalopathy; (2) clinical concepts like treatment resistance; (3) and syndromes like juvenile myoclonic epilepsy. We developed and evaluated the performance of computable phenotypes for these examples using electronic health record data at one center.

METHODS

We identified gold standard cohorts for neonatal hypoxic-ischemic encephalopathy, pediatric treatment-resistant epilepsy, and juvenile myoclonic epilepsy via existing registries and review of clinical notes. From the electronic health record, we extracted diagnostic and procedure codes for all children with a diagnosis of epilepsy and seizures. We used these codes to develop computable phenotypes and evaluated by sensitivity, positive predictive value, and the F-measure.

RESULTS

For neonatal hypoxic-ischemic encephalopathy, the best-performing computable phenotype (HIE ICD-9/10 and [brain magnetic resonance imaging (MRI) or electroencephalography (EEG) within 120 days of life] and absence of commonly miscoded conditions) had high sensitivity (95.7%, 95% confidence interval [CI] 85-99), positive predictive value (100%, 95% CI 95-100), and F measure (0.98). For treatment-resistant epilepsy, the best-performing computable phenotype (3 or more antiseizure medicines in the last 2 years or treatment-resistant ICD-10) had a sensitivity of 86.9% (95% CI 79-93), positive predictive value of 69.6% (95% CI 60-79), and F-measure of 0.77. For juvenile myoclonic epilepsy, the best performing computable phenotype (JME ICD-10) had poor sensitivity (52%, 95% CI 43-60) but high positive predictive value (90.4%, 95% CI 81-96); the F measure was 0.66.

CONCLUSION

The variable accuracy of our computable phenotypes (hypoxic-ischemic encephalopathy high, treatment resistance medium, and juvenile myoclonic epilepsy low) demonstrates the heterogeneity of success using administrative data to identify cohorts important for pediatric epilepsy research.

Prevalence, healthcare resource utilization and mortality of Lennox-Gastaut syndrome: retrospective linkage cohort study

PURPOSE

To retrospectively investigate the prevalence, demography, antiseizure medication (ASM) usage, healthcare resource utilization (HCRU), and mortality of patients with Lennox-Gastaut syndrome (LGS) in primary and secondary care in the UK.

METHODS

Patients with confirmed LGS were anonymously identified from the UK Clinical Practice Research Datalink (CPRD) GOLD database (01/01/1987-31/1b0/2018) using the LGS Read Code (F250500). Probable LGS was identified using the International Classification of Diseases-10/Read Code for epilepsy (Hospital Episode Statistics [HES]/CPRD) plus rufinamide prescription. Period prevalence was calculated based on patients enrolled in CPRD GOLD and alive in 2017. CPRD data were linked to HES to calculate HCRU, and to the Office for National Statistics mortality registry.

RESULTS

Period prevalence of LGS was 0.578/10,000 (n = 180), with 74 and 106 patients identified with confirmed (0.289/10,000) and probable LGS (0.420/10,000). Mean (max) ASM usage was ~1 (3) per year. In confirmed LGS, valproate (72%), lamotrigine (69%), and clobazam (66%) were the most commonly prescribed ASMs. HCRU (per patient-year) was similar in confirmed and probable LGS and mostly consisted of primary care general practitioner consultations (4-6), outpatient visits (5-10), inpatient admissions (1-4), and A&E visits (1). During the follow-up period, 18 patients died with crude mortality rates of 6.12 (confirmed LGS) and 4.17 (probable LGS) deaths per 1000 person-years.

CONCLUSION

Prevalence of LGS appears low in the UK. The similarly high HCRU and mortality rates in confirmed and probable LGS support the validity and specificity of the probable LGS algorithm and high burden of LGS.

Anti-seizure medications for Lennox-Gastaut syndrome

BACKGROUND

Lennox-Gastaut syndrome (LGS) is an age-specific epilepsy syndrome characterised by multiple seizure types, including drop seizures. LGS has a characteristic electroencephalogram, an onset before age eight years and an association with drug resistance. This is an updated version of the Cochrane Review published in 2013.

OBJECTIVES

To assess the efficacy and tolerability of anti-seizure medications (ASMs) for LGS.

SEARCH METHODS

We searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 28 February 2020) on 2 March 2020. CRS Web includes randomised controlled trials (RCTs) or quasi-RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL); the Specialised Registers of Cochrane Review Groups, including Cochrane Epilepsy; PubMed; Embase; ClinicalTrials.gov; and the World Health Organization's International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We contacted pharmaceutical companies and colleagues in the field to seek any unpublished or ongoing studies.

SELECTION CRITERIA

We considered RCTs, including cross-over trials, of ASMs for LGS in children and adults. We included studies of ASMs used as either monotherapy or as an add-on (adjunctive) therapy. We excluded studies comparing different doses of the same ASM.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures, including independent, dual assessment for risk of bias and application of the GRADE approach to rate the evidence certainty for outcomes.

MAIN RESULTS

We found no trials of ASM monotherapy. The review included 11 trials (1277 participants; approximately 11 weeks to 112 weeks follow-up after randomisation) using add-on ASMs for LGS in children, adolescents and adults. Two studies compared add-on cannabidiol (two doses) with add-on placebo in children and adolescents only. Neither study reported overall seizure cessation or reduction. We found high-certainty evidence that 72 more people per 1000 (confidence interval (CI) 4 more to 351 more) had adverse events (AE) leading to study discontinuation with add-on cannabidiol, compared to add-on placebo (two studies; 396 participants; risk ratio (RR) 4.90, 95% CI 1.21 to 19.87). One study compared add-on cinromide with add-on placebo in children and adolescents only. We found very low-certainty evidence that 35 more people per 1000 (CI 123 fewer to 434 more) had 50% or greater average reduction of overall seizures with add-on cinromide compared to add-on placebo (one study; 56 participants; RR 1.15, 95% CI 0.47 to 2.86). This study did not report participants with AE leading to study discontinuation. One study compared add-on clobazam (three doses) with add-on placebo. This study did not report overall seizure cessation or reduction. We found high-certainty evidence that 106 more people per 1000 (CI 0 more to 538 more) had AE leading to study discontinuation with add-on clobazam compared to add-on placebo (one study; 238 participants; RR 4.12, 95% CI 1.01 to 16.87). One study compared add-on felbamate with add-on placebo. No cases of seizure cessation occurred in either regimen during the treatment phase (one study; 73 participants; low-certainty evidence). There was low-certainty evidence that 53 more people per 1000 (CI 19 fewer to 716 more) with add-on felbamate were seizure-free during an EEG recording at the end of the treatment phase, compared to add-on placebo (RR 2.92, 95% CI 0.32 to 26.77). The study did not report overall seizure reduction. We found low-certainty evidence that one fewer person per 1000 (CI 26 fewer to 388 more) with add-on felbamate had AE leading to study discontinuation compared to add-on placebo (one study, 73 participants; RR 0.97, 95% CI 0.06 to 14.97). Two studies compared add-on lamotrigine with add-on placebo. Neither study reported overall seizure cessation. We found high-certainty evidence that 176 more people per 1000 (CI 30 more to 434 more) had ≥ 50% average seizure reduction with add-on lamotrigine compared to add-on placebo (one study; 167 participants; RR 2.12, 95% CI 1.19 to 3.76). We found low-certainty evidence that 40 fewer people per 1000 (CI 68 fewer to 64 more) had AE leading to study-discontinuation with add-on lamotrigine compared to add-on placebo (one study; 169 participants; RR 0.49, 95% CI 0.13 to 1.82). Two studies compared add-on rufinamide with add-on placebo. Neither study reported seizure cessation. We found high-certainty evidence that 202 more people per 1000 (CI 34 to 567 more) had ≥ 50% average seizure reduction (one study; 138 participants; RR 2.84, 95% CI 1.31 to 6.18). We found low-certainty evidence that 105 more people per 1000 (CI 17 fewer to 967 more) had AE leading to study discontinuation with add-on rufinamide compared to add-on placebo (one study; 59 participants; RR 4.14, 95% CI 0.49 to 34.86). One study compared add-on rufinamide with another add-on ASM. This study did not report overall seizure cessation or reduction. We found low-certainty evidence that three fewer people per 1000 (CI 75 fewer to 715 more) had AE leading to study discontinuation with add-on rufinamide compared to another add-on ASM (one study; 37 participants; RR 0.96, 95% CI 0.10 to 9.57). One study compared add-on topiramate with add-on placebo. This study did not report overall seizure cessation. We found low-certainty evidence for ≥ 75% average seizure reduction with add-on topiramate (one study; 98 participants; Peto odds ratio (Peto OR) 8.22, 99% CI 0.60 to 112.62) and little or no difference to AE leading to study discontinuation compared to add-on placebo; no participants experienced AE leading to study discontinuation (one study; 98 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

RCTs of monotherapy and head-to-head comparison of add-on ASMs are currently lacking. However, we found high-certainty evidence for overall seizure reduction with add-on lamotrigine and rufinamide, with low-certainty evidence for AE leading to study discontinuation compared with add-on placebo or another add-on ASM. The evidence for other add-on ASMs for overall seizure cessation or reduction was low to very low with high- to low-certainty evidence for AE leading to study discontinuation. Future research should consider outcome reporting of overall seizure reduction (applying automated seizure detection devices), impact on development, cognition and behaviour; future research should also investigate age-specific efficacy of ASMs and target underlying aetiologies.

Epidemiology, healthcare resource use, and mortality in patients with probable Lennox-Gastaut syndrome: A population-based study on German health insurance data

OBJECTIVE

This retrospective study examined patients with probable Lennox-Gastaut syndrome (LGS) identified from German healthcare data.

METHODS

This 10-year study (2007-2016) assessed healthcare insurance claims information from the Vilua Healthcare research database. A selection algorithm considering diagnoses and drug prescriptions identified patients with probable LGS. To increase the sensitivity of the identification algorithm, two populations were defined: all patients with probable LGS (broadly defined) and only those with a documented epilepsy diagnosis before 6 years of age (narrowly defined). This specific criterion was used as LGS typically has a peak seizure onset between age 3 and 5 years. Primary analyses were prevalence and demographics; secondary analyses included healthcare costs, hospitalization rate and length of stay (LOS), medication use, and mortality.

RESULTS

In the final year of the study, 545 patients with broadly defined probable LGS (mean [range] age: 31.4 [2-89] years; male: 53%) were identified. Using the narrowly defined probable LGS definition, the number of patients was reduced to 102 (mean [range] age: 7.4 [2-14] years; male: 52%). Prevalence of broadly defined and narrowly defined probable LGS was 39.2 and 6.5 per 100,000 people. During the 10-year study, 208 patients with narrowly defined probable LGS were identified and followed up for 1379 patient-years. The mean annual cost of healthcare was €22,787 per patient-year (PPY); greatest costs were attributable to inpatient care (33%), home nursing care (13%), and medication (10%). Mean annual healthcare costs were significantly greater for those with prescribed rescue medication (45% of patient-years) versus those without (€33,872 vs. €13,785 PPY, p < 0.001). Mean (standard deviation [SD]) annual hospitalization rate was 1.6 (2.0) PPY with mean (SD) annual LOS of 22.7 (46.0) days. Annual hospitalization rate was significantly greater in those who were prescribed rescue medication versus those who were not (2.2 [2.3] vs. 1.1 [1.6] PPY, p < 0.001). The mean (SD) number of different medications prescribed was 11.3 (7.3) PPY and 33.8 (17.0) over the entire observable time per patient (OET); antiepileptic drugs only accounted for 2.1 (1.1) of the medications prescribed PPY and 3.8 (2.0) OET. Over the 10-year study period, mortality in patients with narrowly defined probable LGS was significantly higher than the matched control population (six events [2.88%] vs. oneevent [0.01%], p < 0.001).

CONCLUSION

Annual healthcare costs incurred by patients with probable LGS in Germany were substantial, and mostly attributable to inpatient care, home nursing care, and medication. Patients prescribed with rescue medication incurred significantly greater costs than those who were not. Patients with narrowly defined probable LGS had a higher mortality rate versus control populations.

Management of Lennox-Gastaut syndrome beyond childhood: A comprehensive review

Lennox-Gastaut syndrome (LGS) is a childhood-onset epileptic encephalopathy characterized by multiple types of medically intractable seizures, cognitive impairment, and generalized slow spike-wave discharges in electroencephalography (EEG). Although the onset of this epileptic syndrome occurs typically before eight years of age with a peak age between 3 and 5 years, lifelong persistence of the syndrome is usual. The evolution of clinical features, EEG findings, and paucity of knowledge about LGS among adult health care providers can make LGS significantly underdiagnosed in the adult population. Management of LGS remains problematic beyond childhood due to intractable seizures, the difficult transition from pediatric to adult neurologists, challenging behaviors, impaired cognition, poor quality of life, and disabled social life. In focusing on the management of LGS beyond childhood, this narrative review describes medical and surgical management of epilepsy, the transition from pediatric to adult care, and management of other common comorbidities associated with LGS. Several antiepileptic drugs (AEDs) such as lamotrigine, topiramate, felbamate, rufinamide, clobazam, and Epidiolex (pure pharmaceutical grade cannabidiol (CBD) oil) have been noted to be effective in well-designed, randomized controlled trials. Other non-pharmacological therapies, such as vagus nerve stimulation, ketogenic diet, and epilepsy surgery, have been frequently utilized in the management of intractable seizures associated with LGS. However, effective management of LGS requires a broader perspective to not only control seizures but improve the quality of life by addressing cognitive and behavioral problems, sleep disturbances, physical disability, social disability, and educational and employment challenges.

Expanding the Treatment Landscape for Lennox-Gastaut Syndrome: Current and Future Strategies

Lennox-Gastaut syndrome (LGS), a childhood-onset severe developmental and epileptic encephalopathy (DEE), is an entity that encompasses a heterogenous group of aetiologies, with no single genetic cause. It is characterised by multiple seizure types, an abnormal EEG with generalised slow spike and wave discharges and cognitive impairment, associated with high morbidity and profound effects on the quality of life of patients and their families. Drug-refractory seizures are a hallmark and treatment is further complicated by its multiple morbidities, which evolve over the patient's lifetime. This review provides a comprehensive overview of the current and future options for the treatment of seizures associated with LGS. Six treatments are specifically indicated as adjunct therapies for the treatment of seizures associated with LGS in the US: lamotrigine, clobazam, rufinamide, topiramate, felbamate and most recently cannabidiol. These therapies have demonstrated reductions in drop seizures in 15%-68% of patients across trials, with responder rates (≥ 50% reduction in drop seizures) of 37%-78%. Valproate is still the preferred first-line treatment, generally in combination with lamotrigine or clobazam. Other treatments frequently used off-label include the broad spectrum anti-epileptic drugs (AED) levetiracetam, zonisamide and perampanel, while recent evidence from observational studies has indicated that a newer AED, the levetiracetam analogue brivaracetam, may be effective and well tolerated in LGS patients. Other treatments in clinical development include fenfluramine in late phase III, perampanel, soticlestat-OV953/TAK-953, carisbamate and ganaxolone. Non-pharmacologic interventions include the ketogenic diet, vagus nerve stimulation and surgical interventions; these are also expanding, with the potential for less invasive techniques for corpus callosotomy that have promise for reducing complications. However, despite these advancements, patients continue to experience a significant burden. Because LGS is not a single entity, tailoring of treatment is needed as opposed to a 'one size fits all' approach. Further research is needed into the underlying aetiologies and pathophysiology of LGS, together with advancements in treatments that encompass the spectrum of seizures associated with this complex syndrome.

Validating Coding for the Identification of Pediatric Treatment Resistant Epilepsy Patients

The International Classification of Diseases (ICD) system includes sub codes to indicate that an individual with epilepsy is treatment resistant. These codes would be a valuable tool to identify individuals for quality improvement and population health, as well as for recruitment into clinical trials. However, the accuracy of these codes is unclear. We performed a single center cross sectional study to understand the accuracy of ICD codes for treatment resistant epilepsy. We identified 344 individuals, roughly half with treatment resistant epilepsy The ICD code had a sensitivity of 90% (147 of 164) and specificity of 86% (155 of 180). The miscoding of children with refractory epilepsy was attributed to the following reasons: 5 patients had epilepsy surgery, 4 had absence epilepsy, 4 patients were seen by different providers, and 1 patient was most recently seen in movement disorders clinic. ICD codes accurately identify children with treatment resistant epilepsy.

Cost-Effectiveness of Cannabidiol Adjunct Therapy versus Usual Care for the Treatment of Seizures in Lennox-Gastaut Syndrome

BACKGROUND

Cannabidiol (CBD) is a novel therapy for the treatment of Lennox-Gastaut Syndrome (LGS), a rare, treatment-refractory epileptic encephalopathy. Two pivotal trials found CBD 20 mg/kg/day conferred a reduction from baseline in median drop seizure frequency of 44% and 42%, respectively, compared with 22% and 17%, respectively, in the usual care arms. No economic evaluations have been published to date. This analysis assessed the cost effectiveness of CBD adjunct therapy compared with usual care alone in LGS from the US payer perspective.

METHODS

We developed a lifetime horizon Markov decision analytic model. Efficacy, healthcare costs (2020 US$), and health state utilities were ascertained from published clinical trials, retrospective analyses, and time trade-off interviews conducted in the UK, respectively. Fifteen-year-old patients entering the model transitioned to states representing a percentage reduction in drop seizure frequency from baseline, where they remained until reverting back to baseline drop seizure frequency, or death. One-way and probabilistic sensitivity analyses were conducted to evaluate parameter uncertainty, and scenario analyses investigated the impact of various assumptions. Costs and outcomes were discounted at 3%.

RESULTS

Compared with usual care alone, CBD yielded 0.7 additional quality-adjusted life-years (QALYs) and $314,900 additional healthcare expenditure, resulting in $451,800 per QALY. Uncertainty in health state utilities were the largest contributor to uncertainty in the results. Results from the 5000-simulation probabilistic sensitivity analysis indicated a 0% chance of CBD being cost effective at a $150,000 per QALY willingness-to-pay threshold, with a 95% credible range for the incremental cost-effectiveness ratio of $325,300-$690,000 per QALY.

CONCLUSION

CBD does not appear to be a cost-effective therapeutic option in LGS patients at a willingness-to-pay threshold of $150,000/QALY.

Machine learning applications in epilepsy

Machine learning leverages statistical and computer science principles to develop algorithms capable of improving performance through interpretation of data rather than through explicit instructions. Alongside widespread use in image recognition, language processing, and data mining, machine learning techniques have received increasing attention in medical applications, ranging from automated imaging analysis to disease forecasting. This review examines the parallel progress made in epilepsy, highlighting applications in automated seizure detection from electroencephalography (EEG), video, and kinetic data, automated imaging analysis and pre-surgical planning, prediction of medication response, and prediction of medical and surgical outcomes using a wide variety of data sources. A brief overview of commonly used machine learning approaches, as well as challenges in further application of machine learning techniques in epilepsy, is also presented. With increasing computational capabilities, availability of effective machine learning algorithms, and accumulation of larger datasets, clinicians and researchers will increasingly benefit from familiarity with these techniques and the significant progress already made in their application in epilepsy.

Development of a classifier to identify patients with probable Lennox-Gastaut syndrome in health insurance claims databases via random forest methodology

Objective: Describe the development of a claims-based classifier utilizing machine learning to identify patients with probable Lennox-Gastaut syndrome (LGS) from six state Medicaid programs. Methods: Patients were included if they had ≥2 medical claims ≥30 days apart for specified or unspecified epilepsy, excluding those with ≥1 claim for petit mal status. The LGS classifier utilized a random forest algorithm, a compilation of thousands of binary decision trees in which machine-generated predictor variables split the data set into branches that predict the presence or absence of LGS. To construct the splitting rules, the importance of each candidate variable was determined by calculating the mean decrease in Gini impurity. Training and testing were performed on two data sets (30% and 70%) using a "true" LGS and non-LGS patient population. Performance was compared with logistic regression and single tree methodology. Results: Using a 60% probability threshold, which yielded the highest sensitivity (97.3%) and specificity (95.6%), the classifier identified approximately 4% of patients with epilepsy as probable LGS. The most important input variables included number of distinct antiepileptic drugs received, epilepsy-related outpatient/inpatient visits, electroencephalogram procedures and claims for delayed development. The random forest methodology outperformed logistic regression and single tree methodology. Most of the important LGS predictor characteristics identified by the classifier were statistically significantly associated with LGS status (p < .05). Conclusions: The claims-based LGS classifier showed high sensitivity and specificity, outperformed single tree and logistic regression methodologies and identified a prevalence of probable LGS that was similar to previously published estimates.

The direct cost of seizure events in severe childhood-onset epilepsies: A retrospective claims-based analysis

OBJECTIVE

The objective of the study was to assess the direct cost of medically treated seizure events in severe childhood-onset epilepsies. Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC) are representative conditions associated with frequent intractable seizures.

METHODS

Commercial and Medicaid insurance claims from 2010 to 2015 were queried to identify patients with possible LGS, possible DS, or TSC, having ≥2 years of continuous insurance from the date of first epilepsy/seizure diagnosis or antiepileptic drug (AED) fill (index date). Utilization and cost data in patients with and without seizure events requiring acute treatment were evaluated for two years postindex. Medically treated seizure events resulting in minor, moderate, severe, and no injury were included. Average costs were normalized to 2017 dollars at 3% per annum and reported for each cohort, by insurance type and degree of injury.

RESULTS

Among 9754 patients, 55.4-58.8% of LGS, 47.7-55.8% of DS, and 13.7-28.0% of TSC cohorts had ≥1 medically treated seizure event, depending on insurance type. Events during two-year postindex averaged 2.8-3.3 in LGS, 3.1-3.3 in DS, and 1.9-2.2 in TSC; cost per event averaged $8147-$14,759 in LGS, $4637-$8751 in DS, and $5335-$9672 in TSC. In patients with events, average all-cause costs per-patient-per-year (PPPY) were $71,512-$84,939 in LGS; $31,278-$43,758 in DS; and $42,997-$48,330 in TSC.

CONCLUSIONS

Patients with intractable seizures having at least one medically treated seizure event incur substantial all-cause costs. Our results can be used to inform cost effectiveness and budget impact models to estimate the value of existing and future treatments for these and similar conditions.

Burden of illness in patients with possible Lennox-Gastaut syndrome: A retrospective claims-based study

OBJECTIVE

Lennox-Gastaut syndrome (LGS) is a severe and treatment-resistant epilepsy syndrome characterized by multiple subtypes of intractable seizures, moderate to severe cognitive impairment, and slow spike-wave complexes on electroencephalographic (EEG) recordings. Lennox-Gastaut syndrome is also associated with increased risk for injury, reduced quality of life, long-term disability, and early mortality. By evaluating private and public US medical insurance claims, we quantified healthcare utilization and direct costs in patients with possible LGS.

METHODS

Commercial and Medicaid insurance claims (Truven Health Analytics) from October 2010 to September 2015 were queried to identify patients with intractable epilepsy, intellectual disability, ≥1 prescription for selected antiepileptic drugs (AEDs), and ≥2 years of continuous enrollment. To identify patients with LGS in the absence of a specific International Classification of Diseases ICD-9 diagnosis code, current or prior rufinamide use was selected as a disease indicator of LGS per previously published methodology. Characteristics significantly predictive of rufinamide use were identified with multivariate regression by comparing groups with and without LGS, then assessed in non-rufinamide users fulfilling all other inclusion criteria. Controls without epilepsy, seizures, or prescriptions for selected AEDs were matched to patients with possible LGS by age, gender, US region, and dates of insurance coverage. Average healthcare utilization and costs per patient per year (PPPY) were evaluated for a 2-year postindex period and compared between the cohort with LGS and controls by insurance type. Costs were normalized to 2017 dollars at 3% per annum.

RESULTS

In the study, 6019 patients with possible LGS (53% male, mean age of 13 years, in both insurance groups) were identified: 2270 with commercial insurance and 3749 with Medicaid. The cohort with LGS used >8 times more services and >7 times more drugs than controls (all p < 0.001) in both insurance groups. The biggest contributors to service use PPPY were outpatient physician visits and home health services in the commercial-insured cohort with LGS and other outpatient visits and home health services in the Medicaid-insured cohort with LGS. Average total costs PPPY (services + drugs) were significantly higher for the cohort with LGS vs. controls: $65,026 (SD $34,324) vs. $2442 (SD $10,670) for commercial-insured and $63,930 (SD $45,761) vs. $3849 (SD $13849) for Medicaid-insured patients. The biggest cost contributors PPPY were inpatient care in the commercial-insured cohort with LGS and home health services in the Medicaid-insured cohort with LGS.

CONCLUSIONS

Patients with possible LGS have significantly higher healthcare utilization and costs than patients without epilepsy or seizures. Our results suggest that direct costs associated with LGS are substantial and highlight the need for new and effective treatments.

Evolution and course of early life developmental encephalopathic epilepsies: Focus on Lennox-Gastaut syndrome

OBJECTIVES

Developmental encephalopathic epilepsies (DEEs) are characterized by refractory seizures, disability, and early death. Opportunities to improve care and outcomes focus on West syndrome/infantile spasms (WS/IS). Lennox-Gastaut syndrome (LGS) is almost as common but receives little attention. We examined initial presentations of DEEs and their evolution over time to identify risk and indicators of developing LGS.

METHODS

Data are from the Connecticut Study of Epilepsy, a prospective, longitudinal study of 613 children with newly diagnosed epilepsy recruited in 1993-1997. Central review of medical records permitted classification of epilepsy syndromes at diagnosis and at reclassification 2, 5, and 9 years later. DEEs were compared to other epilepsies for seizure and cognitive outcomes and mortality. Analyses examined the evolution of DEE syndromes after initial presentation, with specific comparisons made between WS/IS and LGS. Statistical analyses were performed with t tests and chi-square tests.

RESULTS

Fifty-eight children (9.4%) had DEEs, median onset age = 1.1 years (interquartile range ([IQR] 0.3-1.3) in DEEs and 6.0 years (IQR 3.0-9.0) in other epilepsies (P < 0.001). DEEs vs other epilepsies had more pharmacoresistance (71% vs 18%), intellectual disability (84% vs 11%), and mortality (21% vs <1%; all P < 0.001). During follow-up, the form of epilepsy evolved in 33 children. WS/IS was the most common initial diagnosis (N = 23) and in 5 children WS/IS evolved later. LGS was diagnosed initially in 4 children (1 later revised) and in 22 by the end of follow-up, including 7 evolving from WS/IS and 12 from nonsyndromic generalized, focal, or undetermined epilepsies. Evolution to LGS took a median of 1.9 years. LGS developed in 13% of infants, including 9% of those who did not present initially with WS/IS.

SIGNIFICANCE

DEEs account for disproportionate amounts of pharmacoresistance, disability, and early mortality. LGS often has a window between initial presentation and full expression. LGS should become targeted for early detection and prevention.

Changes in functional brain network topology after successful and unsuccessful corpus callosotomy for Lennox-Gastaut Syndrome

Corpus callosotomy (CC) is an effective palliative surgical treatment for patients with Lennox-Gastaut Syndrome (LGS). However, research on the long-term functional effects of CC is sparse. We aimed to investigate these effects and their associated clinical conditions over the two years after CC. Long-term clinical EEG recordings of 30 patients with LGS who had good and bad seizure outcome after CC were collected and retrospectively studied. It was found that CC caused brain network 'hubs' to shift from paramedian to lateral regions in the good-recovery group, which reorganized the brain network into a more homogeneous state. We also found increased local clustering coefficients in patients with bad outcomes and decreases, implying enhanced network integration, in patients with good outcomes. The small worldness of brain networks in patients with good outcomes increased in the two years after CC, whereas it decreased in patients with bad outcomes. The covariation of small-worldness with the rate of reduction in seizure frequency suggests that this can be used as an indicator of CC outcome. Local and global network changes during the long-term state might be associated with the postoperative recovery process and could serve as indicators for CC outcome and long-term LGS recovery.

Lennox-Gastaut syndrome: a comprehensive review

Lennox-Gastaut syndrome (LGS) is considered an epileptic encephalopathy and is defined by a triad of multiple drug-resistant seizure types, a specific EEG pattern showing bursts of slow spike-wave complexes or generalized paroxysmal fast activity, and intellectual disability. The prevalence of LGS is estimated between 1 and 2% of all patients with epilepsy. The etiology of LGS is often divided into two groups: identifiable (genetic-structural-metabolic) in 65 to 75% of the patients and LGS of unknown cause in others. Lennox-Gastaut syndrome may be considered as secondary network epilepsy. The seizures in LGS are usually drug-resistant, and complete seizure control with resolution of intellectual and psychosocial dysfunction is often not achievable. Reduction in frequency of the most incapacitating seizures (e.g., drop attacks and tonic-clonic seizures) should be the major objective. Valproate, lamotrigine, and topiramate are considered to be the first-line drugs by many experts. Other effective antiepileptic drugs include levetiracetam, clobazam, rufinamide, and zonisamide. The ketogenic diet is an effective and well-tolerated treatment option. For patients with drug resistance, a further therapeutic option is surgical intervention. Corpus callosotomy is a palliative surgical procedure that aims at controlling the most injurious seizures. Finally, vagus nerve stimulation offers reasonable seizure improvement. The long-term outcome for patients with LGS is generally poor. This syndrome is often associated with long-term adverse effects on intellectual development, social functioning, and independent living.