Prevalence of epilepsy and seizures in the Navajo Nation 1998-2002

Neurological Care within the Indian Health Service

American Indians and Alaska Natives (AI/AN) are the Indigenous peoples of the United States. According to the U.S. Census Bureau, approximately 9.7 million people self-identified as AI/AN (alone or in combination with other races), representing 2.9% of the total U.S. population. These people represent diverse groups of discrete Tribes, each with their language, culture, and geographic home. As part of the conquest and settlement of North America, some Indigenous peoples signed treaties with the U.S. government, surrendering their lands in return for various government commitments, including health care. The Indian Health Service (IHS) was born out of these agreements. The IHS is an agency in the U.S. Department of Health and Human Services under the U.S. Public Health Service. The IHS provides a comprehensive health service delivery system for approximately 2.7 million AI/AN who belong to 574 federally recognized Tribes/nations in 37 states. The aim of this paper is to make recommendations regarding the initiation of sustainable neurology care in marginalized or underserved populations by reviewing 40 years of neurology care provision within the IHS. We will discuss (1) the IHS, (2) neurological care provided within the IHS, including midlevel provider extension of neurology care and traditional medical care, and (3) select neurological diagnoses within AI/AN populations. Marginalized populations, including those in the United States that are rural, remote, or low socioeconomic status, lack access to specialty neurology care. This includes many AI/AN. The IHS has developed novel solutions to promote specialty care, including neurology. Notably, initial IHS investments in full-time neurology providers have led to more robust neurology care, often receiving attention from university programs. This suggests that an initial investment in stable on-site full-time neurology services provides a path to potential sustainable care for marginalized populations.

On the Dependence of the Critical Success Index (CSI) on Prevalence

The critical success index (CSI) is an established metric used in meteorology to verify the accuracy of weather forecasts. It is defined as the ratio of hits to the sum of hits, false alarms, and misses. Translationally, CSI has gained popularity as a unitary outcome measure in various clinical situations where large numbers of true negatives may influence the interpretation of other, more traditional, outcome measures, such as specificity (Spec) and negative predictive value (NPV), or when unified interpretation of positive predictive value (PPV) and sensitivity (Sens) is needed. The derivation of CSI from measures including PPV has prompted questions as to whether and how CSI values may vary with disease prevalence (P), just as PPV estimates are dependent on P, and hence whether CSI values are generalizable between studies with differing prevalences. As no detailed study of the relation of CSI to prevalence has been undertaken hitherto, the dataset of a previously published test accuracy study of a cognitive screening instrument was interrogated to address this question. Three different methods were used to examine the change in CSI across a range of prevalences, using both the Bayes formula and equations directly relating CSI to Sens, PPV, P, and the test threshold (Q). These approaches showed that, as expected, CSI does vary with prevalence, but the dependence differs according to the method of calculation that is adopted. Bayesian rescaling of both Sens and PPV generates a concave curve, suggesting that CSI will be maximal at a particular prevalence, which may vary according to the particular dataset.

The epidemiology of epilepsy in older adults: A narrative review by the ILAE Task Force on Epilepsy in the Elderly

In an aging world, it is important to know the burden of epilepsy affecting populations of older persons. We performed a selective review of epidemiological studies that we considered to be most informative, trying to include data from all parts of the world. We emphasized primary reports rather than review articles. We reviewed studies reporting the incidence and prevalence of epilepsy that focused on an older population as well as studies that included a wider age range if older persons were tabulated as a subgroup. There is strong evidence that persons older than approximately 60 years incur an increasing risk of both acute symptomatic seizures and epilepsy. In wealthier countries, the incidence of epilepsy increases sharply after age 60 or 65 years. This phenomenon was not always observed among reports from populations with lower socioeconomic status. This discrepancy may reflect differences in etiologies, methods of ascertainment, or distribution of ages; this is an area for more research. We identified other areas for which there are inadequate data. Incidence data are scarcer than prevalence data and are missing for large areas of the world. Prevalence is lower than would be expected from cumulative incidence, possibly because of remissions, excess mortality, or misdiagnosis of acute symptomatic seizures as epilepsy. Segmentation by age, frailty, and comorbidities is desirable, because "epilepsy in the elderly" is otherwise too broad a concept. Data are needed on rates of status epilepticus and drug-resistant epilepsy using the newer definitions. Many more data are needed from low-income populations and from developing countries. Greater awareness of the high rates of seizures among older adults should lead to more focused diagnostic efforts for individuals. Accurate data on epilepsy among older adults should drive proper allocation of treatments for individuals and resources for societies.

Prescription patterns and dosages of antiepileptic drugs in prevalent patients with epilepsy in Taiwan: A nationwide retrospective cross-sectional study

OBJECTIVE

To evaluate the prescription patterns and prescribed daily dose (PDD)/defined daily dose (DDD) ratios of antiepileptic drugs (AEDs) in prevalent patients with epilepsy in Taiwan.

MATERIALS AND METHODS

A nationwide retrospective cross-sectional study was conducted for prevalent patients with epilepsy in 2016 using the Taiwanese National Health Insurance Research Database. The prescription records of AEDs of all prevalent patients with epilepsy were retrieved. The mean PDDs and PDD/DDD ratios of AEDs in adult patients were obtained to evaluate dosing adequacy. A chi-square test and two-sample t test were used to analyze the differences in AED prescription patterns and dosages, respectively, among patients with different ages, sexes, comorbidities, and therapeutic approaches.

RESULTS

A total of 118,937 prevalent patients with epilepsy were enrolled. The predominant therapeutic approach was monotherapy, especially in the elder adults, accounting for 82.9% of elder adult patients with epilepsy. The proportion of AED monotherapy was higher in patients with dementia (78.9%) and stroke (80.6%). The top three antiepileptic monotherapies were valproic acid (28.7%), levetiracetam (19.1%), and phenytoin (16.9%); however, oxcarbazepine (22.8%) was substituted for carbamazepine (3.9%) as monotherapy for patients aged 0-17 years. Among adult patients with epilepsy, the PDD/DDD ratio of each AED in monotherapy was less than 1.00. The mean PDD of each AED was higher in polytherapy than in monotherapy (p < 0.01), except for lacosamide. The mean PDDs of all evaluated AEDs in monotherapy were lower in elder adult patients than in younger adult patients, most of which reached statistical significance (p < 0.001).

CONCLUSIONS

In Taiwan, valproic acid was the most prescribed AED for prevalent patients with epilepsy. The mean PDDs of most AEDs were lower than the DDDs developed by the World Health Organization.

Pregnancy-related complications and risk of postpartum readmission for seizures and epilepsy: A national study

OBJECTIVE

Peripartum seizures remain a leading cause of maternal morbidity and mortality worldwide. Therefore, recognition of high-risk individuals is essential. We aimed to determine the rate and identify risk factors for postpartum seizure/epilepsy readmissions.

METHODS

In this retrospective cohort study, the Nationwide Readmissions Database was used to identify index admissions for delivery and readmissions for seizures in the year 2013, defined by International Classification of Disease, Ninth Revision, Clinical Modification codes for epilepsy, convulsions, and eclampsia in the primary diagnostic position. Logistic regression analysis was used to examine 30-day readmission for seizures as well as associations between demographic, medical, psychiatric, and pregnancy-related factors.

RESULTS

There were 1 633 714 index admissions for delivery, with a 30-day readmission rate for seizures/epilepsy of 19.69 per 100 000 index admissions. The mean age of index participants was 28.6 years (SD = 5.8). Postpartum 30-day readmissions for eclampsia represented 80% of seizure/epilepsy readmissions. Higher income was associated with lower odds of seizure/epilepsy readmission (odds ratio [OR] = 0.50, 95% confidence interval [CI] = 0.34-0.72, P = .03) for the highest income group. Eclampsia (OR = 19.9, 95% CI = 9.38-42.2, P < .001), preexisting epilepsy (OR = 10.63, 95% CI = 6.43-17.56, P < .001), pre-eclampsia (OR = 3.23, 95% CI = 2.31-4.51, P < .001), and gestational hypertension (OR = 2.78, 95% CI = 1.94-3.98, P < .001) were associated with readmission for seizures.

SIGNIFICANCE

Readmissions for seizures are fortunately rare, but are important to minimize given morbidity and mortality. Most seizure readmissions occurring within 30 days postpartum were coded as eclampsia rather than convulsions or pre-existing epilepsy. These findings suggest that early identification of women with pre-eclampsia and eclampsia may play a role in the prevention of postpartum seizures. Women with these risk factors should be identified to optimize care and monitored closely for seizure-associated complications.

CDC-supported epilepsy surveillance and epidemiologic studies: A review of progress since 1994

To report progress, to identify gaps, and to plan epilepsy surveillance and research activities more effectively, the Centers for Disease Control and Prevention (CDC) Epilepsy Program has summarized findings from selected CDC-supported surveillance and epidemiologic studies about epilepsy from 1994 through 2019. We identified publications supported by CDC funding and publications conducted by the CDC Epilepsy Program alone or with partners. We included only epilepsy surveillance and epidemiologic studies focusing on epilepsy burden, epilepsy-related outcomes, and healthcare utilization. We describe the findings of these studies in the following order: 1)prevalence; 2)incidence; 3)epilepsy-related outcomes by selected demographic characteristics; 4)cysticercosis or neurocysticercosis (NCC); 5)traumatic brain injury (TBI); 6)comorbidity; 7)mortality; 8)access to care; 9)quality of care; and 10) cost. We have characterized these findings in relation to the scope of the first three domains of the 2012 Institute of Medicine report on epilepsy and its relevant first four recommendations. From 1994 through 2019, 76 publications on epilepsy-related epidemiologic and surveillance studies were identified. Over the past 25 years, CDC has expanded community, state, and national surveillance on epilepsy and supported epidemiologic studies by using multiple assessment methods and validated case-ascertainment criteria to identify epilepsy burden, epilepsy-related outcomes, and healthcare utilization in the general population or in population subgroups. Among identified research opportunities, studies on epilepsy incidence and risk factors, mortality, and cost are considered as important surveillance gaps. Other remaining gaps and suggested surveillance strategies are also proposed. Findings from this review may help epilepsy researchers and other stakeholders reference and prioritize future activities for epidemiologic and surveillance studies in epilepsy.

An estimation of global volume of surgically treatable epilepsy based on a systematic review and meta-analysis of epilepsy

OBJECTIVEEpilepsy is one of the most common neurological disorders, yet its global surgical burden has yet to be characterized. The authors sought to compile the most current epidemiological data to quantify global prevalence and incidence, and estimate global surgically treatable epilepsy. Understanding regional and global epilepsy trends and potential surgical volume is crucial for future policy efforts and resource allocation.METHODSThe authors performed a systematic literature review and meta-analysis to determine the global incidence, lifetime prevalence, and active prevalence of epilepsy; to estimate surgically treatable epilepsy volume; and to evaluate regional trends by WHO regions and World Bank income levels. Data were extracted from all population-based studies with prespecified methodological quality across all countries and demographics, performed between 1990 and 2016 and indexed on PubMed, EMBASE, and Cochrane. The current and annual new case volumes for surgically treatable epilepsy were derived from global epilepsy prevalence and incidence.RESULTSThis systematic review yielded 167 articles, across all WHO regions and income levels. Meta-analysis showed a raw global prevalence of lifetime epilepsy of 1099 per 100,000 people, whereas active epilepsy prevalence is slightly lower at 690 per 100,000 people. Global incidence was found to be 62 cases per 100,000 person-years. The meta-analysis predicted 4.6 million new cases of epilepsy annually worldwide, a prevalence of 51.7 million active epilepsy cases, and 82.3 million people with any lifetime epilepsy diagnosis. Differences across WHO regions and country incomes were significant. The authors estimate that currently 10.1 million patients with epilepsy may be surgical treatment candidates, and 1.4 million new surgically treatable epilepsy cases arise annually. The highest prevalences are found in Africa and Latin America, although the highest incidences are reported in the Middle East and Latin America. These regions are primarily low- and middle-income countries; as expected, the highest disease burden falls disproportionately on regions with the fewest healthcare resources.CONCLUSIONSUnderstanding of the global epilepsy burden has evolved as more regions have been studied. This up-to-date worldwide analysis provides the first estimate of surgical epilepsy volume and an updated comprehensive overview of current epidemiological trends. The disproportionate burden of epilepsy on low- and middle-income countries will require targeted diagnostic and treatment efforts to reduce the global disparities in care and cost. Quantifying global epilepsy provides the first step toward restructuring the allocation of healthcare resources as part of global healthcare system strengthening.

Accuracy and utility of using administrative healthcare databases to identify people with epilepsy: a protocol for a systematic review and meta-analysis

INTRODUCTION

In an increasingly digital age for healthcare around the world, administrative data have become rich and accessible tools for potentially identifying and monitoring population trends in diseases including epilepsy. However, it remains unclear (1) how accurate administrative data are at identifying epilepsy within a population and (2) the optimal algorithms needed for administrative data to correctly identify people with epilepsy within a population. To address this knowledge gap, we will conduct a novel systematic review of all identified studies validating administrative healthcare data in epilepsy identification. We provide here a protocol that will outline the methods and analyses planned for the systematic review.

METHODS AND ANALYSIS

The systematic review described in this protocol will be conducted to follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE and Embase will be searched for studies validating administrative data in epilepsy published from 1975 to current (01 June 2018). Included studies will validate the International Classification of Disease (ICD), Ninth Revision (ICD-9) onwards (ie, ICD-9 code 345 and ICD-10 codes G40-G41) as well as other non-ICD disease classification systems used, such as Read Codes in the UK. The primary outcome will be providing pooled estimates of accuracy for identifying epilepsy within the administrative databases validated using sensitivity, specificity, positive and negative predictive values, and area under the receiver operating characteristic curves. Heterogeneity will be assessed using the I² statistic and descriptive analyses used where this is present. The secondary outcome will be the optimal administrative data algorithms for correctly identifying epilepsy. These will be identified using multivariable logistic regression models. 95% confidence intervals will be quoted throughout. We will make an assessment of risk of bias, quality of evidence, and completeness of reporting for included studies.

ETHICS AND DISSEMINATION

Ethical approval is not required as primary data will not be collected. Results will be disseminated in peer-reviewed journals, conference presentations and in press releases.

PROSPERO REGISTRATION

CRD42017081212.

Validity of health insurance data to identify people with epilepsy

BACKGROUND

Large administrative databases may prove useful to assess epilepsy-related comorbidity and mortality. Despite their increased use, their validity as data source in epilepsy is yet under-ascertained.

METHODS

Achmea is a large Dutch health insurance company covering about 25% of the population. We performed a retrospective cohort study using data from the Achmea Health Insurance Database (AHID) over the period 2006-2009. To assess the validity of epilepsy codes in the AHID, we randomly invited 1000 individuals (age 18-75 years insured by Achmea), attending an epilepsy centre or a district hospital during 2006-2009, to participate. Informed consent was provided and 293 were eligible for inclusion. We compared the diagnostic codes for epilepsy in AHID with the diagnosis in their case-notes (reference standard). As additional measure of validity, we compared prevalence of epilepsy codes in AHID (based on anonymized data of all 26.297 subjects with this code in AHID) with epilepsy prevalence rates in the general Dutch population to estimate an age-specific standardized prevalence ratio.

RESULTS

We identified 293 participants with an epilepsy code in AHID. The majority (278) of them had a definite or possible diagnosis of epilepsy in the case-notes; i.e. a positive predictive value of 0.95 (95% CI 0.92-0.97). The overall prevalence of epilepsy codes in the AHID was slightly higher than the putative prevalence in the general Dutch population (7.4/1.000 vs. 6.8/1.000) with a Standardized Prevalence Ratio of 1.08 (95% CI: 1.08-1.09).

CONCLUSIONS

Our findings demonstrate the validity of AHID data for a diagnosis of epilepsy and confirm previous work on using administrative data for epilepsy research.

An update on the prevalence and incidence of epilepsy among older adults

OBJECTIVE

To estimate the prevalence and incidence of epilepsy among beneficiaries of Arizona Medicare aged 65 and over.

METHODS

An analysis of Medicare administrative claims data for 2009-2011 for the State of Arizona was conducted. Epilepsy was defined as a beneficiary who had either≥one claim with diagnostic code of 345.xx (epilepsy) or at least two claims with diagnosis code of 780.3x (seizure) ≥30days apart. Stroke-related and psychiatric comorbidities were determined by diagnostic codes. Average annual prevalence and incidence were calculated and stratified by demographic characteristics and comorbidities. Odds ratios (OR) and 95% confidence intervals (CI) were calculated as measures of effect for prevalence and incidence and the chi-square statistic was calculated to compare the proportions of epilepsy cases with and without comorbidities (alpha=0.05).

RESULTS

The overall average annual prevalence and incidence over the study period was 15.2/1000 and 6.1/1000, respectively. Relative to the 65-69 age group and White beneficiaries, the highest prevalence was observed for beneficiaries 85 years or older (19.8/1000, OR 1.66, 95% CI 1.53-1.81) and Native Americans (21.2/1000, OR 1.42, 95% CI 1.25-1.62). In contrast, the highest incidence rates were observed for beneficiaries 85 years and older (8.5/1000, OR 1.82, 95% CI 1.60-2.07) and for Black beneficiaries (8.7/1000, OR 1.44, 95% CI 1.12-1.86). The incidence rate for Native Americans was not significantly different from that for White beneficiaries (6.2/1000, OR 1.02, 95% CI 0.81-1.29). More than one quarter of all cases (25.7%) and 31% of incident cases had either stroke-related and/or psychiatric comorbidities (all p-values < 0.001).

CONCLUSIONS

Epilepsy is a significant neurological disease among Medicare beneficiaries 65 years and older. Beneficiaries aged 85 and older and Black and Native Americans experienced higher rates of epilepsy than other demographic subgroups compared to White beneficiaries.

Perioperative Risk in Patients With Epilepsy Undergoing Total Joint Arthroplasty

BACKGROUND

Epilepsies is a spectrum of brain disorders ranging from severe, life threatening, and disabling to more benign, but little is known about its impact in the perioperative arthroplasty setting. We sought to determine whether epileptic patients undergoing elective total joint arthroplasty (TJA) would be at increased risk for in-hospital complications and death, prolonged stay, and nonroutine discharge.

METHODS

Using discharge records from the Nationwide Inpatient Sample (2002-2011), we identified 6,054,344 patients undergoing elective primary TJA, of whom 31,865 (0.5%) were identified as having epilepsy. Comparisons of perioperative outcomes were performed by multivariable logistic regression modeling.

RESULTS

Patients with epilepsy were associated with increased in-hospital mortality (odds ratio [OR] 2.03, 95% confidence interval [CI] 1.57-2.62) and morbidity, including (in decreasing order of magnitude of effect estimate): mechanical ventilation (OR 1.74, 95% CI 1.56-1.94), induced mental disorder (OR 1.70, 95% CI 1.56-1.85), stroke (OR 1.63, 95% CI 1.23-2.15), pneumonia (OR 1.34, 95% CI 1.21-1.49), and ileus or gastrointestinal events (OR 1.26, 95% CI 1.12-1.42). Epilepsy was associated with higher risk for blood transfusion (OR 1.30, 95% CI 1.27-1.33), prolonged hospital stay (OR 1.14, 95% CI 1.11-1.17), and nonroutine discharge (OR 1.54, 95% CI 1.50-1.58). We found no association with inpatient thromboembolic events, acute renal failure, and myocardial infarction.

CONCLUSION

Patients with epilepsy are at increased risk for early postoperative complications (especially mechanical ventilation, induced mental disorder, and stroke) and resource utilization after elective joint arthroplasty. Greater awareness of epilepsy and its health consequences may contribute to improvements in the perioperative management of TJA patients.

Estimating the Prevalence of Treated Epilepsy Using Administrative Health Data and Its Validity: ESSENCE Study

Background and Purpose

Few of the epidemiologic studies of epilepsy have utilized well-validated nationwide databases. We estimated the nationwide prevalence of treated epilepsy based on a comprehensive medical payment database along with diagnostic validation.

Methods

We collected data on patients prescribed of antiepileptic drugs (AEDs) from the Health Insurance Review and Assessment service, which covers the entire population of Korea. To assess the diagnostic validity, a medical records survey was conducted involving 6,774 patients prescribed AEDs from 43 institutions based on regional clusters and referral levels across the country. The prevalence of treated epilepsy was estimated by projecting the diagnostic validity on the number of patients prescribed AEDs.

Results

The mean positive predictive value (PPV) for epilepsy was 0.810 for those prescribed AEDs with diagnostic codes that indicate epilepsy or seizure (Diagnosis-E), while it was 0.066 for those without Diagnosis-E. The PPV tended to decrease with age in both groups, with lower values seen in females. The prevalence was 3.84 per 1,000, and it was higher among males, children, and the elderly.

Conclusions

The prevalence of epilepsy in Korea was comparable to that in other East Asian countries. The diagnostic validity of administrative health data varies depending on the method of case ascertainment, age, and sex. The prescriptions of AEDs even without relevant diagnostic codes should be considered as a tracer for epilepsy.

Mortality and Morbidity During Delivery Hospitalization Among Pregnant Women With Epilepsy in the United States

IMPORTANCE

Between 0.3% and 0.5% of all pregnancies occur among women with epilepsy. Evidence suggests an increase in perinatal morbidity and mortality among women with epilepsy. However, these risks have not been quantified in large population-based samples.

OBJECTIVE

To report on the risk for death and adverse outcomes at the time of delivery for women with epilepsy in the United States.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of pregnant women identified through delivery hospitalization records from the 2007-2011 Nationwide Inpatient Sample. From this representative sample of 20% of all US hospitals, we obtained a weighted sample of delivery hospitalizations from 69 385 women with epilepsy and 20 449 532 women without epilepsy.

MAIN OUTCOMES AND MEASURES

Obstetrical outcomes including maternal death, cesarean delivery, length of stay, preeclampsia, preterm labor, and stillbirth.

RESULTS

Women with epilepsy had a risk of death during delivery hospitalization of 80 deaths per 100 000 pregnancies, significantly higher than the 6 deaths per 100 000 pregnancies found among women without epilepsy (adjusted odds ratio [OR], 11.46 [95% CI, 8.64-15.19]). Women with epilepsy were also at a heightened risk for other adverse outcomes, including preeclampsia (adjusted OR, 1.59 [95% CI, 1.54-1.63]), preterm labor (adjusted OR, 1.54 [95% CI, 1.50-1.57]), and stillbirth (adjusted OR, 1.27 [95% CI, 1.17-1.38]), and had increased health care utilization, including an increased risk of cesarean delivery (adjusted OR, 1.40 [95% CI, 1.38-1.42]) and prolonged length of hospital stay (>6 days) among both women with cesarean deliveries (adjusted OR, 2.13 [95% CI, 2.03-2.23]) and women with vaginal deliveries (adjusted OR, 2.60 [95% CI, 2.41-2.80]).

CONCLUSIONS AND RELEVANCE

Findings suggest that women with epilepsy are at considerably heightened risk for many adverse outcomes during their delivery hospitalization, including a more than 10-fold increased risk of death, and that increased clinical attention is imperative for these pregnancies.

Prevalence of pediatric epilepsy in low-income rural Midwestern counties

Epilepsy is one of the most common disabling neurological disorders, but significant gaps exist in our knowledge about childhood epilepsy in rural populations. The present study assessed the prevalence of pediatric epilepsy in nine low-income rural counties in the Midwestern United States overall and by gender, age, etiology, seizure type, and syndrome. Multiple sources of case identification were used, including medical records, schools, community agencies, and family interviews. The prevalence of active epilepsy was 5.0/1000. Prevalence was 5.1/1000 in males and 5.0/1000 in females. Differences by age group and gender were not statistically significant. Future research should focus on methods of increasing study participation in rural communities, particularly those in which research studies are rare.

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.

Increasing utilization of pediatric epilepsy surgery in the United States between 1997 and 2009

OBJECTIVE

To examine national trends of pediatric epilepsy surgery usage in the United States between 1997 and 2009.

METHODS

We performed a serial cross-sectional study of pediatric epilepsy surgery using triennial data from the Kids' Inpatient Database from 1997 to 2009. The rates of epilepsy surgery for lobectomies, partial lobectomies, and hemispherectomies in each study year were calculated based on the number of prevalent epilepsy cases in the corresponding year. The age-race-sex adjusted rates of surgeries were also estimated. Mann-Kendall trend test was used to test for changes in the rates of surgeries over time. Multivariable regression analysis was also performed to estimate the effect of time, age, race, and sex on the annual incidence of epilepsy surgery.

RESULTS

The rates of pediatric epilepsy surgery increased significantly from 0.85 epilepsy surgeries per 1,000 children with epilepsy in 1997 to 1.44 epilepsy surgeries per 1,000 children with epilepsy in 2009. An increment in the rates of epilepsy surgeries was noted across all age groups, in boys and girls, all races, and all payer types. The rate of increase was lowest in blacks and in children with public insurance. The overall number of surgical cases for each study year was lower than 35% of children who were expected to have surgery, based on the estimates from the Connecticut Study of Epilepsy.

SIGNIFICANCE

In contrast to adults, pediatric epilepsy surgery numbers have increased significantly in the past decade. However, epilepsy surgery remains an underutilized treatment for children with epilepsy. In addition, black children and those with public insurance continue to face disparities in the receipt of epilepsy surgery.

Toward an integrated public health approach for epilepsy in the 21st century

Epilepsy, a complex spectrum of disorders, merits enhanced public health action. In 2012, the Institute of Medicine (IOM) released a seminal report on the public health dimensions of the epilepsies, recommending actions in 7 domains. The report urged a more integrated and coordinated national approach for care centering on the whole patient, including heightened attention to comorbidities and quality of life; more timely referral and access to treatments; and improved community resources, education, stakeholder collaboration, and public communication. The US Department of Health and Human Services responded to this report by accelerating and integrating ongoing initiatives and beginning new ones. This article summarizes recent federally supported activities promoting an integrated public health approach for epilepsy, highlighting progress in response to the landmark 2012 IOM report and identifying opportunities for continued public health action.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

Applying evidence to patient care: from population health to individual patient values

What are the health status and health needs of people with epilepsy? How do clinicians and patients choose between alternative interventions for the same condition? Are health interventions used effectively in the community, and do they improve health? How can we translate findings from regulatory clinical trials to the real world? These and similar questions are the subject of applied translational research. This evolving and broad-ranging area of research involves the application of basic sciences such as epidemiology, biostatistics, economics, and behavioral science to the assessment of health, health interventions, and outcomes. However, despite its palpable importance, applied translational research remains underfunded and underutilized. Using their own innovative research as a prototype, two young and promising investigators provide insights not only into the enormous potential but also the gaps and hurdles of two specific areas of applied translational research, i.e., clinical decision analysis and health services research. The message is clear that if we are to understand and improve the health of people with epilepsy in clinics, hospitals, and communities, we must substantially increase research capacity to address the many gaps that thwart our progress in applied research in epilepsy.

Recommendations for optimal ICD codes to study neurologic conditions: a systematic review

OBJECTIVE

Administrative health data are frequently used for large population-based studies. However, the validity of these data for identifying neurologic conditions is uncertain.

METHODS

This article systematically reviews the literature to assess the validity of administrative data for identifying patients with neurologic conditions. Two reviewers independently assessed for eligibility all abstracts and full-text articles identified through a systematic search of Medline and Embase. Study data were abstracted on a standardized abstraction form to identify ICD code-based case definitions and corresponding sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs).

RESULTS

Thirty full-text articles met the eligibility criteria. These included 8 studies for Alzheimer disease/dementia (sensitivity: 8-86.5, specificity: 56.3-100, PPV: 60-97.9, NPV: 68.0-98.9), 2 for brain tumor (sensitivity: 54.0-100, specificity: 97.0-99.0, PPV: 91.0-98.0), 4 for epilepsy (sensitivity: 98.8, specificity: 69.6, PPV: 62.0-100, NPV: 89.5-99.1), 4 for motor neuron disease (sensitivity: 78.9-93.0, specificity: 99.0-99.9, PPV: 38.0-90.0, NPV: 99), 2 for multiple sclerosis (sensitivity: 85-92.4, specificity: 55.9-92.6, PPV: 74.5-92.7, NPV: 70.8-91.9), 4 for Parkinson disease/parkinsonism (sensitivity: 18.7-100, specificity: 0-99.9, PPV: 38.6-81.0, NPV: 46.0), 3 for spinal cord injury (sensitivity: 0.9-90.6, specificity: 31.9-100, PPV: 27.3-100), and 3 for traumatic brain injury (sensitivity: 45.9-78.0 specificity: 97.8, PPV: 23.7-98.0, NPV: 99.2). No studies met eligibility criteria for cerebral palsy, dystonia, Huntington disease, hydrocephalus, muscular dystrophy, spina bifida, or Tourette syndrome.

CONCLUSIONS

To ensure the accurate interpretation of population-based studies with use of administrative health data, the accuracy of case definitions for neurologic conditions needs to be taken into consideration.

Development and validation of a case definition for epilepsy for use with administrative health data

The objective of this study was to develop and validate coding algorithms for epilepsy using ICD-coded inpatient claims, physician claims, and emergency room (ER) visits. 720/2049 charts from 2003 and 1533/3252 charts from 2006 were randomly selected for review from 13 neurologists' practices as the "gold standard" for diagnosis. Epilepsy status in each chart was determined by 2 trained physicians. The optimal algorithm to identify epilepsy cases was developed by linking the reviewed charts with three administrative databases (ICD 9 and 10 data from 2000 to 2008) including hospital discharges, ER visits and physician claims in a Canadian health region. Accepting chart review data as the gold standard, we calculated sensitivity, specificity, positive, and negative predictive value for each ICD-9 and ICD-10 administrative data algorithm (case definitions). Of 18 algorithms assessed, the most accurate algorithm to identify epilepsy cases was "2 physician claims or 1 hospitalization in 2 years coded" (ICD-9 345 or G40/G41) and the most sensitive algorithm was "1 physician clam or 1 hospitalization or 1 ER visit in 2 years." Accurate and sensitive case definitions are available for research requiring the identification of epilepsy cases in administrative health data.

A systematic review of validated methods for identifying seizures, convulsions, or epilepsy using administrative and claims data

PURPOSE

To systematically review algorithms to identify seizure, convulsion, or epilepsy cases in administrative and claims data, with a focus on studies that have examined the validity of the algorithms.

METHODS

A literature search was conducted using PubMed and the Iowa Drug Information Service database. Reviews were conducted by two investigators to identify studies using data sources from the USA or Canada because these data sources were most likely to reflect the coding practices of Mini-Sentinel data partners.

RESULTS

Eleven studies that validated seizure, convulsion, or epilepsy cases were identified. All algorithms included International Classification of Diseases, Ninth Revision, Clinical Modification code 345.X (epilepsy) and either code 780.3 (convulsions) or code 780.39 (other convulsions). Six studies included 333.2 (myoclonus). In populations that included children, 779.0 (convulsions in newborn) was also fairly common. Positive predictive values (PPVs) ranged from 21% to 98%. Studies that used nonspecific indicators such as presence of an electroencephalogram or anti-epileptic drug (AED) level monitoring had lower PPVs. In studies focusing exclusively on epilepsy as opposed to isolated seizure events, sensitivity ranged from 70% to 99%.

CONCLUSIONS

Algorithm performance was highly variable, so it is difficult to draw any strong conclusions. However, the PPVs were generally best in studies where epilepsy diagnoses were required. Using procedure codes for electroencephalograms or prescription claims for drugs possibly used for epilepsy or convulsions in the absence of a diagnostic code is not recommended. Many newer AEDs require no drug level monitoring, so requiring an AED level monitoring procedure in algorithms to identify epilepsy is not recommended.

Incidence and prevalence of epilepsy among older U.S. Medicare beneficiaries

OBJECTIVE

To determine the prevalence and incidence of epilepsy among U.S. Medicare beneficiaries aged 65 years old and over, and to compare rates across demographic groups.

METHODS

We performed a retrospective analysis of Medicare administrative claims for 2001-2005, defining prevalent cases as persons with ≥1 claim with diagnosis code 345.xx (epilepsy) or 2 or more with diagnosis code 780.3x (convulsion) ≥1 month apart, and incident cases as prevalent cases with 2 years immediately before diagnosis without such claims. Prevalence and incidence rates were calculated for the years 2003-2005 using denominators estimated from a 5% random sample of Medicare beneficiaries. Results were correlated with gender, age, and race.

RESULTS

We identified 282,661 per year on average during 2001-2005 (a total of 704,243 unique cases overall), and 62,182 incident cases per year on average during 2003-2005. Average annual prevalence and incidence rates were 10.8/1,000 and 2.4/1,000. Overall, rates were higher for black beneficiaries (prevalence 18.7/1,000, incidence 4.1/1,000), and lower for Asians (5.5/1,000, 1.6/1,000) and Native Americans (7.7/1,000, 1.1/1,000) than for white beneficiaries (10.2/1,000, 2.3/1,000). Incidence rates were slightly higher for women than for men, and increased with age for all gender and race groups.

CONCLUSIONS

Epilepsy is a significant public health problem among Medicare beneficiaries. Efforts are necessary to target groups at higher risk, such as minorities or the very old, and to provide the care necessary to reduce the negative effects of epilepsy on quality of life.

Validation of self-reported epilepsy for purposes of community surveillance

We evaluated the validity of questions designed to identify lifetime and active epilepsy, medication use, and seizure occurrence on population-based surveys. Subjects were interviewed by telephone, and responses were compared with information in their medical records. Prevalence, sensitivity, specificity, and positive predictive value (PPV) were calculated. The prevalence of ever having been diagnosed with epilepsy was 3.1% by self-report and 2.7% by medical record review. Sensitivity was 84.2%, specificity was 99.2%, and PPV was 73.5% for self-reported lifetime epilepsy, and values were similar for active epilepsy. By comparison, sensitivity was higher and specificity was lower for epilepsy medication use and seizure occurrence. The PPV for seizure occurrence was substantially higher for a recall period of 12 months than for 3 months. These results compare favorably with results for other chronic conditions, such as diabetes and arthritis, and indicate that questionnaires can be used to identify epilepsy at a population level.

Standards for epidemiologic studies and surveillance of epilepsy

Worldwide, about 65 million people are estimated to have epilepsy. Epidemiologic studies are necessary to define the full public health burden of epilepsy; to set public health and health care priorities; to provide information needed for prevention, early detection, and treatment; to identify education and service needs; and to promote effective health care and support programs for people with epilepsy. However, different definitions and epidemiologic methods complicate the tasks of these studies and their interpretations and comparisons. The purpose of this document is to promote consistency in definitions and methods in an effort to enhance future population-based epidemiologic studies, facilitate comparison between populations, and encourage the collection of data useful for the promotion of public health. We discuss: (1) conceptual and operational definitions of epilepsy, (2) data resources and recommended data elements, and (3) methods and analyses appropriate for epidemiologic studies or the surveillance of epilepsy. Variations in these are considered, taking into account differing resource availability and needs among countries and differing purposes among studies.

Future directions for epidemiology in epilepsy

Epidemiology continues to be an important research tool in the study of epilepsy and related disorders, providing a better understanding of the frequency, causes and natural history of the disorder. But, beyond risk factors and seizure prognosis, epidemiological studies advance knowledge of many other aspects of epilepsy. Epidemiological studies are being conducted in a new environment in which high quality neuroimaging and fast through-put genomic technologies have become routine tools in clinical diagnosis and therapeutics. Epilepsy is currently understood, not as a single, homogeneous disorder, but a multitude of different clinical syndromes and disease, each with its own cause(s), natural history, and treatment implications. That is why; the comorbidites of epilepsy represent an important area, amenable to study, as they may ultimately have a greater impact on quality of life than epilepsy itself. In this document we share our thoughts on what we think are the future directions for epidemiology in epilepsy.