The Impact of Interictal Discharges on Performance

PURPOSE OF REVIEW

Our purpose is to review evidence relating to the concept that interictal epileptiform discharges (IEDs) impair brain performance.

RECENT FINDINGS

Sophisticated measures of motor and cognitive performance have clarified older observations, confirming that in both animals and humans, IEDs affect aspects of performance, IED morphology, frequency, anatomical distribution, and duration matter. However, we now know that it is difficult to draw a line between IEDs and seizures, not only by electrical criteria but even by metabolic and molecular measures. IEDs impair performance acutely and probably chronically. Thus, there are good theoretical reasons for suppressing them, but no consensus has been reached on how much effort this deserves. Many antiepileptic medications effective for control of clinical seizures have little effect on IEDs. Better methods of measuring outcomes may allow selection of individual patients for whom treatment aimed at IEDs is worthwhile.

Patient characteristics and treatment patterns in patients with newly diagnosed epilepsy: A US database analysis

OBJECTIVE

The objective of this study was to determine patient characteristics and antiepileptic drug (AED) treatment patterns in patients with newly diagnosed epilepsy in a United States (US) population followed for ≥180 days.

METHODS

In this retrospective cohort study, Commercial, Supplemental Medicare, and Medicaid insurance claims from US-based Truven Health MarketScan® claims database were analyzed for incident epilepsy cases (index date: January 2010-June 2013; prior baseline of 2 years [1 year for ages 1 to <2 years; none for those <1 year]). Cases met epilepsy criteria consistent with the International League Against Epilepsy diagnostic guidelines, with continuous medical and pharmacy enrollment without an epilepsy or seizure diagnosis or AED prescription during baseline. Treatment was classified as monotherapy (one AED for ≥90 continuous days), polytherapy (at least two AEDs for ≥90 days), or untreated (no AED claims but other pharmacy or healthcare claims). Treatment pattern comparisons used matched cohorts across seizure types.

RESULTS

Of 58,757 incident cases, 50,838 had a follow-up of ≥180 days. The median (range) follow-up duration was 529 (180-1096) days. Patient characteristics were similar across seizure types (matched focal vs. generalized epilepsy, N = 9949 each). At 6 and 12 months post-index, 46.8% and 52.2% of patients, respectively, had received AED treatment. Of 29,226 patients receiving treatment, 74.7% and 1.6% received monotherapy and polytherapy for ≥90 days, respectively, as first-line treatment; remaining patients received AED for <90 days and were excluded. The probability of remaining on initial treatment after 1 year was 61.0% for monotherapy and 36.5% for polytherapy. The most common first-line AEDs were levetiracetam (44.4%), phenytoin (6.5%), valproic acid (6.4%), lamotrigine (6.3%), oxcarbazepine (5.7%), topiramate (5.5%), and gabapentin (5.3%).

CONCLUSION

Although the majority of treated patients received AED monotherapy consistent with guidelines, suboptimal rates of AED treatment and persistence of first-line treatment after initial epilepsy diagnosis suggest that efforts are needed to improve patient care.

Practice guideline update summary: Efficacy and tolerability of the new antiepileptic drugs I: Treatment of new-onset epilepsy: Report of the American Epilepsy Society and the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

Objective: To update the 2004 American Academy of Neurology (AAN) guideline for treating new-onset focal or generalized epilepsy (GE) with second- and third-generation antiepileptic drugs (AEDs). Methods: The 2004 AAN criteria was used to systematically review literature (January 2003 to November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength. Results: Several second-generation AEDs are effective for new-onset focal epilepsy. Data are lacking on efficacy in new-onset generalized tonic-clonic seizures, juvenile myoclonic epilepsy, or juvenile absence epilepsy, and on efficacy of third-generation AEDs in new-onset epilepsy. Recommendations: Lamotrigine (LTG) should (Level B) and levetiracetam (LEV) and zonisamide (ZNS) may (Level C) be considered in decreasing seizure frequency in adults with new-onset focal epilepsy. LTG should (Level B) and gabapentin (GBP) may (Level C) be considered in decreasing seizure frequency in patients ≥60 years with new-onset focal epilepsy. Unless there are compelling adverse-effect-related concerns, ethosuximide (ETS) or valproic acid (VPA) should be considered before LTG to decrease seizure frequency in treating absence seizures in childhood absence epilepsy (Level B). No high-quality studies suggest clobazam, eslicarbazepine, ezogabine, felbamate, GBP, lacosamide, LEV, LTG, oxcarbazepine, perampanel, pregabalin, rufinamide, tiagabine, topiramate, vigabatrin, or ZNS is effective in treating new-onset epilepsy because no high-quality studies exist in adults of various ages. A recent FDA strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years old and perampanel as monotherapy received FDA approval.

Practice guideline update summary: Efficacy and tolerability of the new antiepileptic drugs II: Treatment-resistant epilepsy: Report of the American Epilepsy Society and the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

Objective: To update the 2004 American Academy of Neurology (AAN) guideline for managing treatment-resistant (TR) epilepsy with second- and third-generation antiepileptic drugs (AEDs). Methods: 2004 criteria were used to systematically review literature (January 2003 to November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength. Results: Forty-two articles were included. Recommendations: The following are established as effective to reduce seizure frequency (Level A): immediate-release pregabalin and perampanel for TR adult focal epilepsy (TRAFE); vigabatrin for TRAFE (not first-line treatment; rufinamide for Lennox-Gastuat syndrome (LGS) (add-on therapy). The following should be considered to decrease seizure frequency (Level B): lacosamide, eslicarbazepine, and extended-release topiramate for TRAFE (ezogabine production discontinued); immediate- and extended-release lamotrigine for generalized epilepsy with TR generalized tonic-clonic (GTC) seizures in adults; levetiracetam (add-on therapy) for TR childhood focal epilepsy (TRCFE) (1 month to 16 years), TR GTC seizures, and TR juvenile myoclonic epilepsy; clobazam for LGS (add-on therapy); zonisamide for TRCFE (6-17 years); oxcarbazepine for TRCFE (1 month to 4 years). The text presents Level C recommendations. AED selection depends on seizure/syndrome type, patient age, concomitant medications, and AED tolerability, safety, and efficacy. This evidence-based assessment informs AED prescription guidelines for TR epilepsy and indicates seizure types and syndromes needing more evidence. A recent FDA strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years of age and perampanel as monotherapy received FDA approval.

Practice guideline update summary: Efficacy and tolerability of the new antiepileptic drugs II: Treatment-resistant epilepsy

Objective

To update the 2004 American Academy of Neurology guideline for managing treatment-resistant (TR) epilepsy with second- and third-generation antiepileptic drugs (AEDs).

Methods

2004 criteria were used to systemically review literature (January 2003 to November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength.

Results

Forty-two articles were included.

Recommendations

The following are established as effective to reduce seizure frequency (Level A): immediate-release pregabalin and perampanel for TR adult focal epilepsy (TRAFE); vigabatrin for TRAFE (not first-line treatment); rufinamide for Lennox-Gastaut syndrome (LGS) (add-on therapy). The following should be considered to decrease seizure frequency (Level B): lacosamide, eslicarbazepine, and extended-release topiramate for TRAFE (ezogabine production discontinued); immediate- and extended-release lamotrigine for generalized epilepsy with TR generalized tonic-clonic (GTC) seizures in adults; levetiracetam (add-on therapy) for TR childhood focal epilepsy (TRCFE) (1 month–16 years), TR GTC seizures, and TR juvenile myoclonic epilepsy; clobazam for LGS (add-on therapy); zonisamide for TRCFE (6–17 years); oxcarbazepine for TRCFE (1 month–4 years). The text presents Level C recommendations. AED selection depends on seizure/syndrome type, patient age, concomitant medications, and AED tolerability, safety, and efficacy. This evidence-based assessment informs AED prescription guidelines for TR epilepsy and indicates seizure types and syndromes needing more evidence. A recent Food and Drug Administration (FDA) strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years of age and perampanel as monotherapy received FDA approval.

Practice guideline update summary: Efficacy and tolerability of the new antiepileptic drugs I: Treatment of new-onset epilepsy

Objective

To update the 2004 American Academy of Neurology (AAN) guideline for treating new-onset focal or generalized epilepsy with second- and third-generation antiepileptic drugs (AEDs).

Methods

The 2004 AAN criteria were used to systematically review literature (January 2003–November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength.

Results

Several second-generation AEDs are effective for new-onset focal epilepsy. Data are lacking on efficacy in new-onset generalized tonic-clonic seizures, juvenile myoclonic epilepsy, or juvenile absence epilepsy, and on efficacy of third-generation AEDs in new-onset epilepsy.

Recommendations

Lamotrigine (LTG) should (Level B) and levetiracetam (LEV) and zonisamide (ZNS) may (Level C) be considered in decreasing seizure frequency in adults with new-onset focal epilepsy. LTG should (Level B) and gabapentin (GBP) may (Level C) be considered in decreasing seizure frequency in patients ≥60 years of age with new-onset focal epilepsy. Unless there are compelling adverse effect–related concerns, ethosuximide or valproic acid should be considered before LTG to decrease seizure frequency in treating absence seizures in childhood absence epilepsy (level B). No high-quality studies suggest clobazam, eslicarbazepine, ezogabine, felbamate, GBP, lacosamide, LEV, LTG, oxcarbazepine, perampanel, pregabalin, rufinamide, tiagabine, topiramate, vigabatrin, or ZNS is effective in treating new-onset epilepsy because no high-quality studies exist in adults of various ages. A recent Food and Drug Administration (FDA) strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years old and perampanel as monotherapy received FDA approval.

Risk of pharmacokinetic interactions between antiepileptic and other drugs in older persons and factors associated with risk

OBJECTIVE

To determine the frequency of older Americans with epilepsy receiving concomitant prescriptions for antiepileptic drugs (AEDs) and non-epilepsy drugs (NEDs) which could result in significant pharmacokinetic (PK) interaction, and to assess the contributions of racial/ethnic, socioeconomic, and demographic factors.

METHODS

Retrospective analyses of 2008-2010 Medicare claims for a 5% random sample of beneficiaries ≥67 years old in 2009 augmented for minority representation. Prevalent cases had ≥1 ICD-9 345.x or ≥2 ICD-9 780.3x, and ≥1 AED. Among them, incident cases had no seizure/epilepsy claim codes nor AEDs in preceding 365 days. Drug claims for AEDs, and for the 50 most common NEDs within +/- 60 days of the index epilepsy date were tabulated. Interacting pairs of AEDs/NEDs were identified by literature review. Logistic regression models were used to examine factors affecting the likelihood of interaction risk.

RESULTS

Interacting drug pairs affecting NED efficacy were found in 24.5% of incident, 39% of prevalent cases. Combinations affecting AED efficacy were found in 20.4% of incident, 29.3% of prevalent cases. Factors predicting higher interaction risk included having ≥ 1 comorbidity, being eligible for Part D low Income Subsidy, and not living in the northeastern US. Protective factors were Asian race/ethnicity, and treatment by a neurologist.

SIGNIFICANCE

A substantial portion of older epilepsy patients received NED-AED combinations that could cause important PK interactions. The lower frequency among incident vs. prevalent cases may reflect changes in prescribing practices. Avoidance of interacting AEDs is feasible for most persons because of the availability of newer drugs.

Detection of generalized tonic-clonic seizures using surface electromyographic monitoring

Objective

A prospective multicenter phase III trial was undertaken to evaluate the performance and tolerability in the epilepsy monitoring unit (EMU) of an investigational wearable surface electromyographic (sEMG) monitoring system for the detection of generalized tonic–clonic seizures (GTCSs).

Methods

One hundred ninety‐nine patients with a history of GTCSs who were admitted to the EMU in 11 level IV epilepsy centers for clinically indicated video‐electroencephalographic monitoring also received sEMG monitoring with a wearable device that was worn on the arm over the biceps muscle. All recorded sEMG data were processed at a central site using a previously developed detection algorithm. Detected GTCSs were compared to events verified by a majority of three expert reviewers.

Results

For all subjects, the detection algorithm detected 35 of 46 (76%, 95% confidence interval [CI] = 0.61–0.87) of the GTCSs, with a positive predictive value (PPV) of 0.03 and a mean false alarm rate (FAR) of 2.52 per 24 h. For data recorded while the device was placed over the midline of the biceps muscle, the system detected 29 of 29 GTCSs (100%, 95% CI = 0.88–1.00), with a detection delay averaging 7.70 s, a PPV of 6.2%, and a mean FAR of 1.44 per 24 h. Mild to moderate adverse events were reported in 28% (55 of 199) of subjects and led to study withdrawal in 9% (17 of 199). These adverse events consisted mostly of skin irritation caused by the electrode patch that resolved without treatment. No serious adverse events were reported.

Significance

Detection of GTCSs using an sEMG monitoring device on the biceps is feasible. Proper positioning of this device is important for accuracy, and for some patients, minimizing the number of false positives may be challenging.

Safety and tolerability of lacosamide monotherapy in the elderly: A subgroup analysis from lacosamide trials in diabetic neuropathic pain

Objective

To assess the safety profile of lacosamide monotherapy in elderly (≥65 years) subjects with diabetic neuropathic pain (DNP).

Methods

Of 1,863 DNP subjects in double‐blind, randomized, placebo‐controlled trials of lacosamide monotherapy (NCT00861445, NCT00235469, NCT00238524, NCT00135109, NCT00350103), 502 were elderly. Safety data from elderly subjects were compared with that of younger subjects (<65 years) within these DNP trials. It should be noted that lacosamide is approved for the treatment of focal (partial‐onset) seizures; it is not approved/recommended for the treatment of DNP.

Results

Overall, cardiovascular diseases were prevalent in the DNP population, as was the use of cardiac, blood pressure, diabetes, and cholesterol‐lowering medications among both young and elderly subjects. The most frequently reported adverse events (AEs) for lacosamide monotherapy (200, 400, and 600 mg/day combined) in elderly versus younger subjects were dizziness (16.2% vs. 13.2%), nausea (10.0% vs. 9.4%), and headache (8.0% vs. 8.7%). Incidences of cardiac disorder AEs were higher in elderly versus younger subjects receiving placebo (6.2% vs. 3.9%), lacosamide 200 (4.8% vs. 3.3%), lacosamide 400 (7.0% vs. 4.1%), and lacosamide 600 mg/day (7.7% vs. 4.0%). Discontinuation rates because of any AE in the elderly versus younger subjects were similar for placebo (8.8% vs. 7.0%) and lacosamide 200 mg/day (9.6% vs. 11.9%) and higher for lacosamide 400 (25.1% vs. 10.8%) and lacosamide 600 mg/day (52.7% vs. 28.3%).

Significance

Lacosamide monotherapy was well tolerated in elderly subjects with DNP, with an overall AE profile consistent with that reported in epilepsy trials.

Quality Indicator for Epilepsy Treatment 15 (QUIET-15): Intervening after recurrent seizures in the elderly

In this study, we examined the provision of care to older adults with epilepsy and compliance with the "Quality Indicator for Epilepsy Treatment 15" (QUIET-15) measure. We analyzed 2008-2010, 5% random sample of Medicare beneficiaries augmented with data from all beneficiaries who identified as a minority with claims related to seizures (780.3x) or epilepsy (345.xx). Of 36,912 identified epilepsy cases, 12.6% had ≥1 emergency room (ER) visit for seizure(s). For those who presented to ER, among those taking anti-epileptic drugs (AEDs), AED was changed in 15.4%, dose adjusted in 19.7%, and stopped in 14.9%; among those not taking AED, therapy was initiated in 68.5%. In adjusted logistic regressions, African-Americans were more likely to have recurrent seizures than Whites (OR 1.41, 95%CI 1.27-1.56), while Asians were less likely to have recurrent seizures (OR 0.71, 95%CI 0.57-0.89). There were no significant racial/ethnic differences in the likelihood of a post-seizure intervention. The chance of seizure recurrence leading to ER visit decreased with age and increased with the number of comorbidities. Patients with seizure recurrence were more likely to be taking an enzyme-inducing AED (OR 1.69, 95%CI 1.57-1.82) and receiving Part D Low Income Subsidy (OR 1.36, 95%CI 1.22-1.51). The probability of AED change after a seizure was higher for patients with ≥4 comorbidities (OR 1.69, 95%CI 1.25-2.27), patients who saw a neurologist (OR 1.49, 95%CI 1.30-1.70), and patients who were taking an enzyme-inducing AED (OR 1.47, 95%CI 1.27-1.71). Overall, a minority of Medicare beneficiaries experienced seizure recurrence that resulted in an ER visit. However, only half of them received treatment concordant with QUIET-15. Though racial differences were observed in occurrence of seizures, none were noted in the provision of care.

Understanding the burden of focal epilepsy as a function of seizure frequency in the United States, Europe, and Brazil

Objective

To understand the current burden of focal epilepsy (FE) as a function of seizure frequency.

Methods

Patients were identified from the United States (2011, 2012, and 2013), five European countries (EU; France, Germany, Italy, Spain, United Kingdom) (2011 and 2013), and Brazil (2011 and 2012) National Health and Wellness Survey (NHWS), a nationally representative, Internet‐based survey of adults (18+ years). The NHWS collected data on respondents’ quality of life (QoL), health utilities, productivity loss, and healthcare resource utilization. Indirect and direct costs were calculated from the literature. Altogether, 345 of 176,093 (U.S.A.), 73 of 30,000 (United Kingdom), 53 of 30,001 (Germany), 53 of 30,000 (France), 41 of 12,011 (Spain), 37 of 17,500 (Italy), and 71 of 24,000 (Brazil) respondents self‐reported a diagnosis of FE.

Results

Many respondents (U.S.A.: 56.2%; 5EU: 41.6%; Brazil + 5EU: 40.5%) reported persistent seizures (≥1 per year). Over 60% to just over 71% of respondents with FE were treated with antiepileptic drugs (AEDs). In the United States, seizure frequency was associated with hospitalizations, indirect costs (ages 18–60), and total direct costs. For the 5EU and Brazil + 5EU, seizure frequency was associated with physical QoL, health utilities, activity impairment, and emergency room (ER) visits. Additional associations were observed for the 5EU on hospitalizations, indirect costs (ages 18–60), ER visit costs, and total direct costs and for Brazil + 5EU on absenteeism, overall work impairment, and provider visits. Costing was not performed for Brazil + 5EU.

Significance

Around half of the patients had persistent seizures despite most taking an AED in this 2011–2013 dataset. The results support the hypothesis that reducing seizures can improve productivity and reduce resource utilization and associated costs. Regional differences may reflect differences in healthcare systems and selected patient populations. Overall, the results suggest that additional treatment options are needed to improve seizure control and reduce related costs.

What does the U.S. Medicare administrative claims database tell us about initial antiepileptic drug treatment for older adults with new-onset epilepsy?

OBJECTIVE

Disparities in epilepsy treatment are not uncommon; therefore, we examined population-based estimates of initial antiepileptic drugs (AEDs) in new-onset epilepsy among racial/ethnic minority groups of older US Medicare beneficiaries.

METHODS

We conducted retrospective analyses of 2008-2010 Medicare administrative claims for a 5% random sample of beneficiaries augmented for minority representation. New-onset epilepsy cases in 2009 had ≥1 International Classification of Diseases, Ninth Revision (ICD-9) 345.x or ≥2 ICD-9 780.3x, and ≥1 AED, AND no seizure/epilepsy claim codes or AEDs in preceding 365 days. We examined AED use and concordance with Quality Indicators of Epilepsy Treatment (QUIET) 6 (monotherapy as initial treatment = ≥30 day first prescription with no other concomitant AEDs), and prompt AED treatment (first AED within 30 days of diagnosis). Logistic regression examined likelihood of prompt treatment by demographic (race/ethnicity, gender, age), clinical (number of comorbid conditions, neurology care, index event occurring in the emergency room (ER)), and economic (Part D coverage phase, eligibility for Part D Low Income Subsidy [LIS], and ZIP code level poverty) factors.

RESULTS

Over 1 year of follow-up, 79.6% of 3,706 new epilepsy cases had one AED only (77.89% of whites vs. 89% of American Indian/Alaska Native [AI/AN]). Levetiracetam was the most commonly prescribed AED (45.5%: from 24.6% AI/AN to 55.0% whites). The second most common was phenytoin (30.6%: from 18.8% Asians to 43.1% AI/AN). QUIET 6 concordance was 94.7% (93.9% for whites to 97.3% of AI/AN). Only 50% received prompt AED therapy (49.6% whites to 53.9% AI/AN). Race/ethnicity was not significantly associated with AED patterns, monotherapy use, or prompt treatment.

SIGNIFICANCE

Monotherapy is common across all racial/ethnic groups of older adults with new-onset epilepsy, older AEDs are commonly prescribed, and treatment is frequently delayed. Further studies on reasons for treatment delays are warranted. Interventions should be developed and tested to develop paradigms that lead to better care.

Which children receive vigabatrin? Characteristics of pediatric patients enrolled in the mandatory FDA registry

Vigabatrin (Sabril®) is an antiepileptic drug (AED) currently indicated in the US as a monotherapy for patients 1month to 2years of age with infantile spasms (IS) and as adjunctive therapy for patients ≥10years of age with refractory complex partial seizures (rCPS) whose seizures have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss. The approval required an FDA mandated registry. This article describes 5years of demographic and treatment exposure data from US pediatric patients (<17years). Participation is mandatory for all US Sabril® prescribers and patients. A benefit-risk assessment must be documented for patient progression to maintenance therapy. This includes demographic diagnosis and reports of ophthalmologic assessments (where available). Patient data were grouped by age as proxies for indication (IS: <3years, rCPS: ≥3 to <17years). As of August 26, 2014, 5546/6823 enrolled patients were pediatric/total; 4472 (81%) were vigabatrin-naïve. Seventy-one percent of patients were <3years of age; 29% were ≥3 to <17years of age. Etiologies of IS were identified as cryptogenic (21%), symptomatic tuberous sclerosis (17%), and symptomatic other (42%). The majority of patients with IS (56%) attempted no prior treatments; 16% received adrenocorticotropic hormone prior to vigabatrin. A third of patients with IS were receiving 1 concomitant treatment with vigabatrin. For patients with rCPS, 39% attempted 1-3 prior treatments; 27% were receiving 2 concomitant treatments at enrollment. A total of 1852 (41%) patients did not undergo baseline ophthalmological assessment; 25% of patients with IS and 42% of patients with rCPS were exempted for neurologic disabilities. Kaplan-Meier estimates predict that 71% and 65% of vigabatrin-naïve patients with IS and rCPS, respectively, would remain in the registry at 6months. Most pediatric vigabatrin patients have IS as an underlying diagnosis, especially those <3years of age. A proportion of those with rCPS remain on long-term vigabatrin despite the risk of adverse events.

Estimating Epilepsy Incidence and Prevalence in the US Pediatric Population Using Nationwide Health Insurance Claims Data

This study aims to determine prevalence and incidence of epilepsy in the US pediatric population. We analyzed commercial claims and Medicaid insurance claims data between 2008 and 2012. Over 8 million continuously enrolled lives aged 0 to 19 years were included. Our definition of a prevalent case of epilepsy was based on International Classification of Diseases-coded diagnoses of epilepsy or seizures and evidence of prescribed antiepileptic drugs. Incident cases were identified in subjects continuously enrolled for ≥2 years of which the first 2 years had no indication of epilepsy or seizures. The overall prevalence estimate for 2012 was 6.8 per 1,000 children. The overall incidence estimate for 2012 was 104 per 100,000 pediatric population. This study provides estimates of the prevalence and incidence of epilepsy in the US pediatric population, using large claims datasets from multiple US population sectors. The findings appear reasonably representative of the US-insured pediatric population.

Sabril® registry 5-year results: Characteristics of adult patients treated with vigabatrin

Vigabatrin (Sabril®), approved in the US in 2009, is currently indicated as adjunctive therapy for refractory complex partial seizures (rCPS) in patients ≥ 10 years old who have responded inadequately to several alternative treatments and as monotherapy for infantile spasms (IS) in patients 1 month to 2 years of age. Because of reports of vision loss following vigabatrin exposure, FDA approval required a risk evaluation mitigation strategy (REMS) program. Vigabatrin is only available in the US through Support, Help, And Resources for Epilepsy (SHARE), which includes a mandated registry. This article describes 5 years of demographic and treatment exposure data from adult patients (≥ 17 years old) in the US treated with vigabatrin and monitored in the ongoing Sabril® registry. Registry participation is mandatory for all US Sabril® prescribers and patients. A benefit-risk assessment must be documented by the physician for a patient to progress to maintenance therapy, defined as 1 month of vigabatrin treatment for patients with IS and 3 months for patients with rCPS. Ophthalmologic assessments must be documented during and after completion of therapy. As of August 26, 2014, a total of 6823 patients were enrolled in the registry, of which 1200 were adults at enrollment. Of these patients, 1031 (86%) were naïve to vigabatrin. The majority of adult patients (n=783, 65%) had previously been prescribed ≥ 4 AEDs, and 719 (60%) were receiving ≥ 3 concomitant AEDs at vigabatrin initiation. Prescribers submitted an initial ophthalmological assessment form for 863 patients; an ophthalmologic exam was not completed for 300 (35%) patients and thus, were considered exempted from vision testing. Of these patients, 128 (43%) were exempted for neurologic disabilities. Clinicians discontinued treatment in 8 patients because of visual field deficits (VFD) (5 patients naïve to vigabatrin and 3 patients previously exposed). Based on Kaplan-Meier survival estimates, it is estimated that approximately 71%, 55%, and 40% of adult patients naïve to vigabatrin would remain in the registry at 3, 6, and 12 months, respectively. These demographic data suggest that a proportion of adult patients remain on vigabatrin long-term despite the risks of adverse events and significant underlying AED resistance and neurologic disease.

Understanding the burden of idiopathic generalized epilepsy in the United States, Europe, and Brazil: An analysis from the National Health and Wellness Survey

The aim of this study was to understand the current burden of primary generalized tonic-clonic seizures (PGTCS) associated with idiopathic generalized epilepsy (IGE) as a function of seizure frequency. We analyzed data for (IGE) as a proxy measure of PGTCS. Little is known about the quality of life (QoL), health utility, productivity, healthcare resource utilization (HRU), and cost burden of PGTCS or IGE. Patients were identified from the US (2011, 2012, & 2013), 5EU (2011 & 2013), and Brazil (2011 & 2012) National Health and Wellness Survey, a nationally representative, internet-based survey of adults (18+ years). Patients that self-reported a diagnosis of IGE were categorized into seizure frequencies of: ≥1 seizure per week, 1-3 seizures per month, 1-4 seizures per year, or <1 seizure per year. QoL was measured using the SF-36v2 Mental (MCS) and Physical Component Summary (PCS) scores, health utilities with the SF-6D, productivity with the Work Productivity and Activity Impairment (WPAI) questionnaire, and HRU as reported in the past six months. Unit costs were estimated from the literature and multiplied against HRU values to calculate direct costs and WPAI values to calculate indirect costs. Generalized linear regression was utilized to examine the relationship between seizure frequency and each measure of burden with adjustment for covariates. Out of the general population surveyed, IGE was self-reported in 782 of 176,093 (US), 172 of 30,000 (UK), 106 of 30,001 (Germany), 87 of 30,000 (France), 31 of 12,011 (Spain), 22 of 17,500 (Italy), and 34 of 24,000 (Brazil). Persistent seizures (≥1 per year) were reported in over 40% of patients with IGE (10-15% with ≥1 seizure per week, 10-15% with 1-3 seizures per month, 20-25% with 1-4 seizures per year). Over 75% were treated with antiepileptic drugs (AEDs). Compared with those having <1 seizure per year (reference group), patients in the two most frequent seizure categories reported worse MCS and PCS scores. Patients in the three highest seizure frequency groups consistently reported worse health utility scores, and greater presenteeism (attending work while not physically or mentally capable of working), overall work impairment, activity impairment, HRU, indirect costs, and direct costs than the reference group. Despite the availability of AEDs during the year surveyed, a substantial number of patients experienced persistent seizures. Increasing seizure frequency was clearly associated with worse outcomes. The burden of PGTCS and IGE may be proportionally reduced by newer AEDs which may increase the proportion of seizure-free patients or shift more patients into lower seizure frequency categories.

Descriptive epidemiology of epilepsy in the U.S. population: A different approach

OBJECTIVE

Determine prevalence and incidence of epilepsy within two health insurance claims databases representing large sectors of the U.S.

METHODS

A retrospective observational analysis using Commercial Claims and Medicare (CC&M) Supplemental and Medicaid insurance claims data between January 1, 2007 and December 31, 2011. Over 20 million continuously enrolled lives of all ages were included. Our definition of a prevalent case of epilepsy was based on International Classification of Diseases, Ninth Revision, Clinical Modification-coded diagnoses of epilepsy or seizures and evidence of prescribed antiepileptic drugs. Incident cases were identified among prevalent cases continuously enrolled for ≥ 2 years before the year of incidence determination with no epilepsy, seizure diagnoses, or antiepileptic drug prescriptions recorded.

RESULTS

During 2010 and 2011, overall age-adjusted prevalence estimate, combining weighted estimates from all datasets, was 8.5 cases of epilepsy/1,000 population. With evaluation of CC&M and Medicaid data separately, age-adjusted prevalence estimates were 5.0 and 34.3/1,000 population, respectively, for the same period. The overall age-adjusted incidence estimate for 2011, combining weighted estimates from all datasets, was 79.1/100,000 population. Age-adjusted incidence estimates from CC&M and Medicaid data were 64.5 and 182.7/100,000 enrollees, respectively. Incidence data should be interpreted with caution due to possible misclassification of some prevalent cases.

SIGNIFICANCE

The large number of patients identified as having epilepsy is statistically robust and provides a credible estimate of the prevalence of epilepsy. Our study draws from multiple U.S. population sectors, making it reasonably representative of the U.S.-insured population.

Newer antiepileptic drug use and other factors decreasing hospital encounters

A retrospective analysis was conducted in one claims database and was confirmed in a second independent database (covering both commercial and government insurance plans between 11/2009 and 9/2011) for the understanding of factors influencing antiepileptic drug (AED) use and the role of AEDs and other health-care factors in hospital encounters. In both datasets, epilepsy cases were identified by AED use and epilepsy diagnosis coding. Variables analyzed for effect on hospitalization rates were as follows: (1) use of first-generation AEDs or second-generation AEDs, (2) treatment changes, and (3) factors that may affect AED choice. Lower rates of epilepsy-related hospital encounters (encounters with an epilepsy diagnosis code) were associated with use of second-generation AEDs, deliberate treatment changes, and treatment by a neurologist. Epilepsy-related hospital encounters were more frequent for patients not receiving an AED and for those with greater comorbidities. On average, patients taking ≥1 first-generation AED experienced epilepsy-related hospitalizations every 684days, while those taking ≥1second-generation AED were hospitalized every 1001days (relative risk reduction of 31%, p<0.01). Prescriptions for second-generation AEDs were more common among neurologists and among physicians near an epilepsy center. Use of second-generation AEDs, access to specialty care, and deliberate efforts to change medications following epilepsy-related hospital encounters improved outcomes of epilepsy treatment based on average time between epilepsy-related hospital encounters. These factors may be enhanced by public health policies, private insurance reimbursement policies, and education of patients and physicians.