Incidence and prevalence of treated epilepsy among poor health and low-income Americans

Disparities in Epilepsy Diagnosis and Management in High-Income Countries: A Review of the Literature

Purpose of Review

Currently, an estimated 3.4 million people in the United States live with epilepsy. Previous studies have identified health disparities associated with race/ethnicity, socioeconomic status (SES), sex, insurance status, and age in this population. However, there has been a dearth of research addressing these disparities. We performed a literature review of articles published between 2010 and 2020 pertaining to health disparities in people with epilepsy (PWE), identified key factors that contribute to gaps in their care, and discussed possible solutions.

Recent Findings

Health disparities in prevalence, treatment access, time to diagnosis, health care delivery and engagement, and clinical outcomes were identified among individuals who were either of low SES, rural-based, uninsured/underinsured, older patients, patients of color, or female sex.

Summary

Disparities in care for PWE continue to persist. Greater priority should be placed on addressing these gaps intricately tied to sociodemographic factors. Reforms to mitigate health disparities in PWE are necessary for timely diagnosis, effective treatment, and positive long-term outcomes.

Prevalence, demographic and spatial distribution of treated epilepsy in France in 2020: a study based on the French national health data system

BACKGROUND

Although still incomplete, the epidemiology of epilepsy shows substantial variations in the burden of the condition according to demographic, social and territorial characteristics. This study aimed to estimate the prevalence of treated epilepsy and to investigate its demographic and spatial distribution in 2020 in France, a country where the nationwide epidemiological situation of the condition remains largely unknown.

METHODS

We used the French national health data system, which covers nearly the entire population residing in France (over 67 million of inhabitants in metropolitan and overseas departments). Prevalent cases were identified using long-term disease status, hospitalisation for epilepsy (ICD-10 codes G40 or G41), and reimbursements for antiseizure medications and electroencephalograms.

RESULTS

In 2020, we identified 685,122 epilepsy cases, corresponding to an overall prevalence of 10.2 per 1000 inhabitants [95% confidence interval 10.1-10.2], with similar rates in men and women. Estimates were found to increase with age, with an accelerated rise in the second half of the life, which occurred earlier in men than in women. We observed a monotonic gradient of variation with socio-economic deprivation (in non-military metropolitan subjects aged 18-54 years) as well as territorial heterogeneity, with the mountainous centre of France as well as some French overseas departments having the highest prevalence.

CONCLUSIONS

Our results revise upwards the estimation of epilepsy prevalence in France, showing that it now ranks among the highest in developed countries. Our study also confirms the important socio-territorial heterogeneity of the condition that reflects health inequalities in this country.

The Frequency and Precipitating Factors for Breakthrough Seizures in Children with Epilepsy

Background and Purpose

To determine the common precipitating factors for breakthrough seizures in children with epilepsy.

Methods

This retrospective study reviewed the charts of children with epilepsy who were followed up in the pediatric neurology clinic of King Fahad Hospital in Al-Baha region, Saudi Arabia, between January 2015 and August 2022. Children between 1 to 14 years of age who had epilepsy, as per the International League Against Epilepsy definition and received anti-seizure medication with a seizure-free period of at least 2 months before breakthrough seizure episode, were included in the study.

Results

Of the 108 children included in the study, the mean age was 6.8±1.6 years, and among them (55.5%) were male. Most parents (69.5%) were unaware of the triggering factors of seizure. The majority of patients (88%) reported at least one precipitating factor for breakthrough seizures and the most common one was systemic infection associated with fever (52.8%), and then non-compliance to medications in (34.3%) of the patients. In terms of the electroencephalogram, around 84 patients (77.8%) had abnormal electroencephalogram. Finally, monotherapy was maintained in 63.9% of patients.

Conclusions

We conclude that the most common trigger for breakthrough seizure is a systemic infection associated with fever and non-compliance to anti-seizure medications. Increasing the level of awareness by different methods may help limit or even prevent seizures from occurring. Randomized controlled trials could shed light on the adjustment of anti-seizure medications temporarily by increasing the dosage or giving extra doses during the infection to avoid breakthrough seizures.

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.

The burden of epilepsy and unmet need in people with focal seizures

BACKGROUND

Epilepsy is one of the most common neurological conditions worldwide. As a chronic condition, epilepsy imposes a significant burden on people with epilepsy and society. We aimed to assess the burden and unmet need of individuals with epilepsy and their caregivers, focusing on focal seizures, the main type of seizure in adults and children.

METHODS

A targeted evidence review of the burden of epilepsy, focusing on focal seizures, was conducted to identify articles reporting: epidemiology, mortality, morbidity, quality of life (QoL), and costs.

RESULTS

Focal seizures affect up to ∼61% of people with epilepsy. They are associated with an increased risk of injury and premature death than the general population. People with epilepsy also have high comorbidity, particularly depression, anxiety, and cognitive impairments. Higher seizure frequency, adverse treatment events, and employment concerns reduce QoL. A reduction in caregivers' QoL is also often reported. Epilepsy requires long-term treatment accounting for high individual costs. Hospitalizations and antiseizure medications (ASMs) are the leading cost drivers of inpatient management and indirect costs with high unemployment rates, particularly in drug-resistant populations. Despite the advent of new treatments, a high unmet need remains unaddressed; approximately 40% of people with epilepsy are drug-resistant, further increasing the risks associated with epilepsy.

CONCLUSIONS

Our findings highlight a substantial burden of illness and unmet needs in individuals with focal seizures, especially those with drug-resistant epilepsy. Suboptimal treatment options negatively impact QoL and, consequently, a sizeable economic burden indicating the need for new treatments and prioritizing this condition.

Association between social deprivation and incidence of first seizures and epilepsy: a prospective population based cohort

OBJECTIVE

Epidemiologic studies have investigated whether social deprivation is associated with a higher incidence of epilepsy and results are conflicting, especially in children. The mechanisms underlying a potential association are unclear. This study examines whether there is an association between social deprivation and the incidence of first seizures (unprovoked and provoked) and new diagnosis of epilepsy by comparing incidence across an area-level measure of deprivation in a population-based cohort.

METHODS

Multiple methods of case identification followed by individual case validation and classification were carried out in a defined geographical area (population 542,868) to identify all incident cases of first provoked and first unprovoked seizures and new diagnosis of epilepsy presenting during the calendar year 2017. An area-level relative deprivation index, based on ten indicators from census data, was assigned to each patient according to registered address and categorised into quintiles from most to least deprived.

RESULTS

The annual incidence of first unprovoked seizures (n=372), first provoked seizures (n=189) and new diagnosis of epilepsy (n=336) was highest in the most deprived areas compared to the least deprived areas (incidence ratios of 1·79 (95%CI 1·26, 2·52), 1·55 (95%CI 1·04, 2·32) and 1·83 (95%CI 1·28, 2·62), respectively). This finding was evident in both adults and children and in those with structural and unknown aetiologies of epilepsy.

SIGNIFICANCE

The incidence of first seizures and new diagnosis of epilepsy is associated with more social deprivation. The reason for this higher incidence is likely multifactorial.

Learning from the comorbidities of epilepsy

PURPOSE OF REVIEW

Comorbidities are a common feature in epilepsy, but neither the entire spectrum nor the significance of such comorbidities has been fully explored. We review comorbidities associated with epilepsy and their associated burden, provide an overview of relationships, and discuss a new conceptualization of the comorbidities.

RECENT FINDINGS

The epidemiology of the comorbidities of epilepsy and effects on health outcomes, healthcare use, and healthcare expenditures have been partly delineated. Distinct mechanisms of the associations have been suggested but not entirely ascertained. Movement from conceptualizing epilepsy as a condition to a symptom-complex has occurred.

SUMMARY

Comorbidities are common among people with epilepsy and are associated with poorer clinical outcomes and quality of life, greater use of health resources, and increased expenditure. Becoming aware of the associated mechanisms and their uncertainty is central to understanding the relationships between epilepsy and comorbid health conditions, which have implications for diagnosis and screening, medical management, and surgical management. Conceptualizing comorbidities of epilepsy as precipitating factors and epilepsy as the symptom will improve the understanding of epilepsy and catalyze research and improvements in clinical practice.

Incidence of Adult-Onset Epilepsy and the Contributory Role of Neurocysticercosis in a Five-Year, Population-Based, Prospective Study in Rural Ecuador

This prospective cohort study aimed to assess incidence and etiology of adult-onset epilepsy in previously seizure-free Atahualpa residents aged ≥ 20 years. Persons with adult-onset epilepsy occurring over 5 years were identified from annual door-to-door surveys and other overlapping sources. Those who emigrated or declined consent were excluded at the administrative censoring date of the last survey when these subjects were interviewed. Persons who died and those who developed incident epilepsy were censored at the time of these outcomes. Poisson regression models adjusted for demographics, education, alcohol intake, and the length of observation time, were used to estimate annual adult-onset epilepsy incidence rate ratio and cumulative incidence. Systematic neuroimaging screening was offered to participants to get insights on the etiology of epilepsy. Individuals enrolled in this cohort (N = 1,480) contributed to 6,811.6 years of follow-up. Seventeen developed incident adult-onset epilepsy, for an annual incident rate of 249.2 per 100,000 persons-year (95% CI: 130.7-367.7). Cumulative incidence was 1,245.9 per 100,000 persons (95% CI: 653.7-1,838.3) after a mean of 4.6 (SE: 0.06) years of follow-up. Six persons with incident epilepsy had neurocysticercosis (35%). Individuals with neurocysticercosis were six times more likely to develop adult-onset epilepsy than those without this disease (IRR: 6.01; 95% CI: 2.16-16.7), after adjusting for relevant covariates. The attributable fraction of incident adult-onset epilepsy due to neurocysticercosis was 30.9% (95% CI: 25.6-46.2%). This rural Ecuadorian population has a high incidence of adult-onset epilepsy, with neurocysticercosis being an important contributory cause.

Knowledge and attitudes of physical educators toward epilepsy and students with epilepsy: A cross-sectional study from Palestine

OBJECTIVE

The study aimed to test knowledge and attitudes of physical educators in Palestine toward epilepsy and students with epilepsy. The study also aimed to identify the variables that were associated with adequate knowledge and positive attitudes toward epilepsy and students with epilepsy.

METHODS

This study was done in a cross-sectional design among physical educators in Palestinian schools. The questionnaire tested knowledge and attitudes of physical educators using 18-item and 12-statement tests, respectively.

RESULTS

Complete questionnaires were returned by 226 physical educators (response rate = 75.3%). The median knowledge score of the physical educators on the 18-item knowledge test was 50% [33.0%, 61.0] and the median attitudes score of the physical educators on the 12-statemtns was 50.0% [42.0, 58.0]. Higher knowledge scores were associated with age, teaching experience, educational level, having known/interacted with people with epilepsy, and receiving education about epilepsy. Higher attitude scores were associated with gender, age, educational level, place of residence, type of school, having known/interacted with people with epilepsy, and receiving education about epilepsy.

CONCLUSION

Knowledge gaps and negative attitudes toward epilepsy and students with epilepsy were identified among physical educators in Palestine. Appropriately designed interventions are still needed to improve knowledge and correct attitudes of physical educators about epilepsy and students with epilepsy.

Developing a Conceptual Disease Model of Patient Experiences and Identifying Patient-Reported Clinical Outcome Assessments for Use in Trials of Treatments for Focal Onset Seizures

PURPOSE

To identify concepts important to understanding the experiences of adults with focal onset seizures (FOS) and evaluate clinical outcome assessments (COAs) for measuring these concepts in clinical trials of treatments for FOS.

METHODS

A search of published qualitative research, clinical trials, and approved product labels for FOS treatments was performed to develop a conceptual disease model (CDM) of patients' experience of living with FOS. Concepts of interest (COI) were selected, and a second literature search was conducted to identify COAs measuring these concepts. Ten COAs were selected and reviewed to document their development process, evidence of measurement properties, and methods for interpreting change scores using criteria proposed in regulatory guidelines for patient-reported outcomes to support label claims.

RESULTS

Concepts identified from the published literature (13 articles, 1 conference abstract), 24 clinical trials, and 8 product labels were included in a novel CDM. Impacts on physical, cognitive, and social and emotional function were chosen as COI for evaluating treatment outcomes for FOS; the additional concept of social support and coping strategies was chosen to understand patients' lived experiences. From 51 unique COAs identified, 10 were selected based on their potential coverage of the COI; some symptom severity and health-related quality of life (HRQoL) COAs covered multiple COI. Of these 10, 8 COAs evaluated impacts/limitations on physical function, 8 measured social and emotional impacts, and 5 assessed social support and coping strategies. While most assessments had gaps in evidence validating their measurement properties, 2 COAs measuring symptom severity and 1 COA measuring HRQoL had evidence confirming their potential utility in clinical trials to support label claims.

CONCLUSION

This research provides insights into the experience of patients with FOS and identifies COAs that measure concepts considered to support endpoints in clinical trials for FOS.

Collaborative scientific production of epilepsy in Latin America from 1989 to 2018: A bibliometric analysis

Socioeconomic and cultural factors coupled with an inability to control many endemic and emerging diseases have resulted in a growing incidence of epilepsy cases in Latin America. This study aimed to analyze and describe scientific research output trends in epilepsy research for the period 1989-2018. Publications were extracted from Scopus indexed journals. Bibliometric analysis was used to analyze scientific output including number of annual publications, documents, and publication characteristics. A mapping analysis using VOSviewer software visualized collaborative network analysis, co-citation analysis, and keyword co-occurrence analysis. SciVal quantitatively analyzed distribution of countries, institutions, citation counts, H-index, and research collaborative partnerships. A total of 176507 records were initially retrieved after which 5636 were analyzed. Overall, an increasing trend for publication output was observed from 19 articles in 1989 to 342 in 2018; the number of publications significantly increased over the past 20 years (p = 0.0065). The majority of publications were original articles (74.4%). Brazil had the most scientific production (55.2%), followed by Mexico (15.4%) and Argentina (10%). Extra-regional collaboration was primarily with the United States, United Kingdom, and Canada; intraregional collaboration was low. The most common area of investigation by co-occurrences was "diagnostic research" (37.2%), with studies based on electroencephalography and nuclear magnetic resonance. Epilepsy research in Latin America has seen a steady growth with significant increases over the past 20 years. Brazil, Mexico, and Argentina are the most productive countries in the field collaborating primarily with extra-regional countries of high-income.

Impact of variable look-back periods on the incidence rates of chronic diseases using real world data

PURPOSE

Estimating disease incidence based on secondary data requires a look-back period to exclude patients with pre-existing disease from the incidence risk set. However, the optimal length of the look-back period and its impact on incidence rates are often unknown. We studied the impact of the length of the look-back period on incidence rates of 24 different chronic diseases.

METHODS

Everyone residing in Sweden between January 1, 2005 and December 31, 2013 were identified from national registries and followed up to 2 years (through December 31, 2015). Outcome events were identified from inpatient and outpatient hospital contacts and incidence rates were calculated per 100 000 person-years. The length of the look-back period was varied with 6-month increments, starting at 6 months. The maximum look-back period of 9 years was used as reference period.

RESULTS

There were 7 943 807 individuals with a look-back period of at least 9 years (mean age 46.5 years) and a mean follow-up time of 1.97 years. Incidence rates were higher across all diseases when restricting the look-back to 1 year compared to 9 years, with a magnitude of overestimation of the incidence rates between 13% (temporal arteritis) and 174% (type 1 diabetes). However, for most diseases the effect of extending the look-back period beyond 3-5 years appeared comparably small.

CONCLUSIONS

This study illustrates how short look-back periods cause overestimation of the incidence rates of chronic diseases, suggesting that sensitivity analyses with respect to look-back period are considered, particularly using data sources with limited information on past medical history.

Deciphering the surgical treatment gap for drug-resistant epilepsy (DRE): A literature review

Patients with drug-resistant epilepsy (DRE) rarely achieve seizure freedom with medical therapy alone. Despite being safe and effective for select patients with DRE, epilepsy surgery remains heavily underutilized. Multiple studies have indicated that the overall rates of surgery in patients with DRE have stagnated in recent years and may be decreasing, even when hospitalizations for epilepsy-related problems are on the rise. Ultimately, many patients with DRE who might otherwise benefit from surgery continue to have intractable seizures, lacking access to the full spectrum of available treatment options. In this article, we review the various factors accounting for the persistent underutilization of epilepsy surgery and uncover several key themes, including the persistent knowledge gap among physicians in identifying potential surgical candidates, lack of coordinated patient care, patient misconceptions of surgery, and socioeconomic disparities impeding access to care. Moreover, factors such as the cost and complexity of the preoperative evaluation, a lack of federal resource allocation for the research of surgical therapies for epilepsy, and difficulties recruiting patients to clinical trials all contribute to this multifaceted dilemma.

Clinical Implementation of a Parent Questionnaire to Identify Seizures in High-Risk Children

BACKGROUND

This study evaluated the effectiveness of a parent-completed questionnaire for detecting seizures in high-risk children.

METHODS

A 2-part seizure screen for children up to 12 years of age with suspected autism spectrum disorder, developmental delay, or seizure, was implemented in 12 Massachusetts clinics serving populations with high health disparities. Primary care providers and developmental behavioral pediatricians administered part 1, a brief highly sensitive screen. If the result was positive, a research assistant administered part 2, a more detailed screen with higher specificity. Positive part 2 results prompted a specialized assessment by a pediatric neurologist. Screening data were evaluated for detection of seizures or other diagnoses, reason for conducting the screen, and appointment outcomes. Data analysis included chi-squared tests, percentages for categorical variables, and means for numerical data.

RESULTS

Of 207 administered seizure questionnaires, 78% of children screened positive on part 1. Of those, 94% of families completed part 2 by telephone, and 64 individuals screened positive. The screen helped to detect 15 new seizure diagnoses and 35 other neurologic diagnoses. Average time to first scheduled appointment was 23.8 days. The no-show rate was 7%.

CONCLUSIONS

The seizure questionnaire effectively identified seizures and other disorders in a diverse population of high-risk children. Broader use of this low-cost screening tool could improve access to care for children with suspected seizures, increase seizure recognition, and help allocate resources more effectively.

Global, regional, and national burden of epilepsy, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND

Seizures and their consequences contribute to the burden of epilepsy because they can cause health loss (premature mortality and residual disability). Data on the burden of epilepsy are needed for health-care planning and resource allocation. The aim of this study was to quantify health loss due to epilepsy by age, sex, year, and location using data from the Global Burden of Diseases, Injuries, and Risk Factors Study.

METHODS

We assessed the burden of epilepsy in 195 countries and territories from 1990 to 2016. Burden was measured as deaths, prevalence, and disability-adjusted life-years (DALYs; a summary measure of health loss defined by the sum of years of life lost [YLLs] for premature mortality and years lived with disability), by age, sex, year, location, and Socio-demographic Index (SDI; a compound measure of income per capita, education, and fertility). Vital registrations and verbal autopsies provided information about deaths, and data on the prevalence and severity of epilepsy largely came from population representative surveys. All estimates were calculated with 95% uncertainty intervals (UIs).

FINDINGS

In 2016, there were 45·9 million (95% UI 39·9-54·6) patients with all-active epilepsy (both idiopathic and secondary epilepsy globally; age-standardised prevalence 621·5 per 100 000 population; 540·1-737·0). Of these patients, 24·0 million (20·4-27·7) had active idiopathic epilepsy (prevalence 326·7 per 100 000 population; 278·4-378·1). Prevalence of active epilepsy increased with age, with peaks at 5-9 years (374·8 [280·1-490·0]) and at older than 80 years of age (545·1 [444·2-652·0]). Age-standardised prevalence of active idiopathic epilepsy was 329·3 per 100 000 population (280·3-381·2) in men and 318·9 per 100 000 population (271·1-369·4) in women, and was similar among SDI quintiles. Global age-standardised mortality rates of idiopathic epilepsy were 1·74 per 100 000 population (1·64-1·87; 1·40 per 100 000 population [1·23-1·54] for women and 2·09 per 100 000 population [1·96-2·25] for men). Age-standardised DALYs were 182·6 per 100 000 population (149·0-223·5; 163·6 per 100 000 population [130·6-204·3] for women and 201·2 per 100 000 population [166·9-241·4] for men). The higher DALY rates in men were due to higher YLL rates compared with women. Between 1990 and 2016, there was a non-significant 6·0% (-4·0 to 16·7) change in the age-standardised prevalence of idiopathic epilepsy, but a significant decrease in age-standardised mortality rates (24·5% [10·8 to 31·8]) and age-standardised DALY rates (19·4% [9·0 to 27·6]). A third of the difference in age-standardised DALY rates between low and high SDI quintile countries was due to the greater severity of epilepsy in low-income settings, and two-thirds were due to a higher YLL rate in low SDI countries.

INTERPRETATION

Despite the decrease in the disease burden from 1990 to 2016, epilepsy is still an important cause of disability and mortality. Standardised collection of data on epilepsy in population representative surveys will strengthen the estimates, particularly in countries for which we currently have no or sparse data and if additional data is collected on severity, causes, and treatment. Sizeable gains in reducing the burden of epilepsy might be expected from improved access to existing treatments in low-income countries and from the development of new effective drugs worldwide.

FUNDING

Bill & Melinda Gates Foundation.

Mitochondrial damage in hippocampal neurons of rats with epileptic protein expression of Fas and caspase-3

Epilepsy model in rats was established to observe the behavior and pathological changes, and to detect mitochondrial dysfunction, exploring its possible molecular mechanisms. The epileptic status of Sprague-Dawley (SD) rats was induced by intraperitoneal injection of lithium chloride, and the change of behavior was recorded. Electroencephalogram (EEG) was used to measure the abnormal discharge of neurons in rats. The brain tissue was fixed with polyformaldehyde and the paraffin sections were prepared, and the damage of the hippocampal neurons was observed with Nissl staining. Mitochondrial ATP and mitochondrial DNA were examined to assess mitochondrial dysfunction. Finally, qPCR and western blot analysis were used to detect mRNA and protein expression of fatty acid synthetase (Fas), Fas ligand (FasL) and caspase-3 in rat hippocampal neurons. The correlation between the mitochondrial dysfunction of rat hippocampal neurons and Fas and caspase-3 was analyzed. Compared with the normal group rats, the model group showed typical seizures, which were determined by the Racine attack score. EEG of the hippocampus of the model group was recorded in cluster in model group rats. Nissl staining showed a different degree of damage to the hippocampal neurons in the model group compared with normal rats. The mitochondrial ATP content and DNA content of rat hippocampal neurons in the model group were significantly lower than that of normal rats (P<0.01). The qPCR and western blot results showed that the mRNA and protein expression levels of Fas, FasL and caspase-3 were significantly increased in the hippocampus of rat model group (P<0.01). The expression level of Fas and caspase-3 in hippocampal tissues of rats was negatively correlated with mitochondrial DNA content. In conclusion, seizures cause damage of neuron mitochondria in rat hippocampus leading to death of hippocampal neurons, the mitochondrial damage of hippocampal neurons in epileptic rats was closely related to the expression of Fas and caspase-3.

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.

Association of epilepsy and asthma: a population-based retrospective cohort study

Background

Epidemiologic data supporting the epilepsy–asthma association are insufficient. Therefore, we examined this association in this study.

Methods

By using claims data from the National Health Insurance Research Database (Taiwan), we executed a retrospective cohort analysis. Analysis 1 entailed comparing 150,827 patients diagnosed as having incident asthma during 1996–2013 with disease-free controls who were selected randomly during the same period, frequency matched in terms of age and sex. Similarly, analysis 2 entailed comparing 25,274 patients newly diagnosed as having epilepsy with sex- and age-matched controls who were selected randomly. At the end of 2013, we evaluated in analysis 1 the epilepsy incidence and risk and evaluated in analysis 2 the asthma incidence and risk. We applied Kaplan–Meier analysis to derive plots of the proportion of asthma-free seizures.

Results

In analysis 1, the asthma group exhibited a higher epilepsy incidence than did the control group (3.05 versus 2.26 per 1,000 person-years; adjusted hazard ratio: 1.39, 95% CI [1.33–1.45]). We also noted a greater risk of subsequent epilepsy in women and girls. In analysis 2, we determined that the asthma incidence between the control and epilepsy groups did not differ significantly; however, some age subgroups including children and individuals in their 30s had an increased risk. A negative association was found in adolescents. The Kaplan–Meier analysis revealed epilepsy to be positively associated with subsequent onset of asthma within seven years of epilepsy diagnosis.

Discussion

Asthma may be associated with high epilepsy risk, and epilepsy may be associated with high asthma risk among children and individuals in their 30s. Nevertheless, people with epilepsy in other age subgroups should be aware of the possibility of developing asthma within seven years of epilepsy diagnosis.

Effects of carbamazepine combined with vitamin B12 on levels of plasma homocysteine, hs-CRP and TNF-α in patients with epilepsy

The efficacy of carbamazepine combined with vitamin B12 in epilepsy treatment by comparing levels of plasma homocysteine (Hcy), serum TNF-α and hs-CRP in patients with epilepsy before and after treatment was investigated. Fifty-eight patients with epilepsy who were admitted and received treatment in The First People's Hospital of Xuzhou were recruited as subjects, and fifty-eight healthy volunteers were recruited as the control group. Patients were treated with carbamazepine combined with vitamin B12 for a period of three months. The mRNA and protein levels of TNF-α and hs-CRP in serum were measured before and after treatment using semi-quantitative RT-PCR and western blotting, respectively. The plasma Hcy levels were measured as well. Within one year after the 3-month treatment, the frequency and duration of seizure were tracked. After treatment with carbamazepine combined with vitamin B12 for patients with epilepsy, the Hcy level was significantly higher than that before treatment and that in the control group (P<0.01). The mRNA and protein levels of TNF-α and hs-CRP in serum were significantly higher in patients than that in healthy people (P<0.01). After treatment these levels were reduced (P<0.01), but still higher than those in healthy people (P<0.05, P<0.01). After treatment, the frequency and duration of seizures were all reduced (P<0.05, P<0.01). The results suggested that carbamazepine combined with vitamin B12 was effective in treatment of epilepsy by reducing levels of TNF-α and hs-CRP in the serum, but had a risk of increasing the Hcy level.

Non-attendance of vulnerable populations within epilepsy outpatient services in Ireland

BACKGROUND

Outpatient non-attendance is a prevalent issue that contributes to significant wasted clinical resources and can be influenced by a number of complex factors.

AIMS

The aim of this study is to characterize "did not attend" (DNA) rates in three identified subpopulations of epilepsy patients to determine if current care provision models suffice.

METHODS

In this study, we identified all patients residing in social housing, in residential care, and those incarcerated who have been offered appointments by our service. We calculated the total number of appointments issued to each group over their entire interaction with our service and their subsequent non-attendance rate as a group. Additionally, we calculated the baseline DNA rate for our epilepsy clinic as a whole for comparison.

RESULTS

We found that the baseline DNA rate for the clinic as a whole was 18.9%. Those in social housing, in residential care, and incarcerated had significantly higher DNA rates of 24, 20.2, and 54.3%, respectively.

CONCLUSIONS

This study provided evidence that in certain groups of patients, clinicians may need to explore other care delivery models due to high DNA rates.

Diagnostic value and prognostic evaluation of dynamic video-electroencephalogram monitoring in children with epilepsy

The diagnostic and prognostic value of dynamic video-electroencephalogram (V-EEG) monitoring in children with epilepsy were investigated. From February 2014 to February 2016, in total 200 children with epilepsy were selected during their stay in the First Hospital of Qinghuangdao and were randomly allocated to a dynamic and a conventional V-EEG monitoring group (n=100). The detection rate of epileptiform discharges in the two groups was evaluated. The V-EEG monitoring index was used to select treatment methods for patients with epilepsy. After 3 months, the patients were rechecked. Disease features and incidence of epilepsy were recorded. There were no significant differences in the course of disease, seizure frequency and age between the two groups (P>0.05). The detection rate of epileptiform discharges in the dynamic V-EEG was significantly higher than in the routine monitoring group (P<0.01). The accuracy and specificity of monitoring in the V-EEG were significantly higher than in the routine monitoring group (P<0.01). Seizure frequency and number of epilepsy attacks in patients in the V-EEG group were significantly lower than in the routine monitoring group (P<0.01). Dynamic V-EEG can improve epilepsy detection rate. The high accuracy and specificity of dynamic V-EEG suggest that it may be of great clinical value in the diagnosis and prognosis of epilepsy.

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.

Long-term reduction of health care costs and utilization after epilepsy surgery

OBJECTIVE

To assess long-term direct medical costs, health care utilization, and mortality following resective surgery in persons with uncontrolled epilepsy.

METHODS

Retrospective longitudinal cohort study of Medicaid beneficiaries with epilepsy from 2000 to 2008. The study population included 7,835 persons with uncontrolled focal epilepsy ages 18-64 years, with an average follow-up time of 5 years. Of these, 135 received surgery during the study period. To account for selection bias, we used risk-set optimal pairwise matching on a time-varying propensity score, and inverse probability of treatment weighting. Repeated measures generalized linear models were used to model utilization and cost outcomes. Cox proportional hazard was used to model survival.

RESULTS

The mean direct medical cost difference between the surgical group and control group was $6,806 after risk-set matching. The incidence rate ratio of inpatient, emergency room, and outpatient utilization was lower among the surgical group in both unadjusted and adjusted analyses. There was no significant difference in mortality after adjustment. Among surgical cases, mean annual costs per subject were on average $6,484 lower, and all utilization measures were lower after surgery compared to before.

SIGNIFICANCE

Subjects that underwent epilepsy surgery had lower direct medical care costs and health care utilization. These findings support that epilepsy surgery yields substantial health care cost savings.

Prevalence and Incidence of Epilepsy in an Elderly and Low-Income Population in the United States

Background and Purpose

The purpose of this study was to estimate the incidence and prevalence of epilepsy among an elderly and poor population in the United States.

Methods

Arizona Medicaid claims data from January 1, 2008 to December 31, 2010 were used for this analysis. Subjects who were aged ≥65 years and were continuously enrolled in any Arizona Medicaid health plans (eligible to patients with low income) for ≥12 months between January 1, 2008 and December 31, 2009 were considered eligible for inclusion in the study cohort. In addition to meeting the aforementioned criteria, incident and prevalent cases must have had epilepsy-related healthcare claims. Furthermore, incident cases were required to have a 1-year "clean" period immediately preceding the index date. Negative binomial and logistic regression models were used to assess the factors associated with epilepsy incidence and prevalence.

Results

The estimated epilepsy incidence and prevalence for this population in 2009 were 7.9 and 19.3 per 1,000 person-years, respectively. The incidence and prevalence rates were significantly higher for patients with comorbid conditions that were potential risk factors for epilepsy and were of younger age than for their non-comorbid and older counterparts (p<0.05). The prevalence rates were significantly higher for non-Hispanic Blacks and male beneficiaries than for non-Hispanic Whites and female beneficiaries, respectively (p<0.05).

Conclusions

This patient population had higher epilepsy incidence and prevalence compared with the general US population. These differences may be at least in part attributable to their low socioeconomic status.

Does adherence to epilepsy quality measures correlate with reduced epilepsy-related adverse hospitalizations? A retrospective experience

In 2011, the American Academy of Neurology (AAN) established eight epilepsy quality measures (EQMs) for chronic epilepsy treatment to address deficits in quality of care. This study assesses the relationship between adherence to these EQMs and epilepsy-related adverse hospitalizations (ERAHs). A retrospective chart review of 475 new epilepsy clinic patients with an ICD-9 code 345.1-9 between 2010 and 2012 was conducted. Patient demographics, adherence to AAN guidelines, and annual number of ERAHs were assessed. Fisher's exact test was used to assess the relationship between adherence to guidelines (as well as socioeconomic variables) and the presence of one or more ERAH per year. Of the eight measures, only documentation of seizure frequency, but not seizure type, correlated with ERAH (relative risk [RR] 0.343, 95% confidence interval [CI] 0.176-0.673, p = 0.010). Among patients in the intellectually disabled population (n = 70), only review/request of neuroimaging correlated with ERAH (RR 0.128, 95% CI 0.016-1.009, p = 0.004). ERAHs were more likely in African American patients (RR 2.451, 95% CI 1.377-4.348, p = 0.008), Hispanic/Latino patients (RR 4.016, 95% CI 1.721-9.346, p = 0.016), Medicaid patients (RR 2.217, 95% CI 1.258-3.712, p = 0.009), and uninsured patients (RR 2.667, 95% CI 1.332-5.348, p = 0.013). In this retrospective series, adherence to the eight AAN quality measures did not strongly correlate with annual ERAH.

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.

Epilepsy and deprivation, a data linkage study

OBJECTIVE

To investigate whether the link between epilepsy and deprivation is due to factors associated with deprivation (social causation) or factors associated with a diagnosis of epilepsy (social drift).

METHODS

We reviewed electronic primary health care records from 2004 to 2010, identifying prevalent and incident cases of epilepsy and recording linked deprivation scores. Logistic and Poisson regression models were used to calculate odds ratios and incidence rate ratios. The change in deprivation was measured 10 years after the initial diagnosis of epilepsy for a cohort of people.

RESULTS

Between 2004 and 2010, 8.1 million patient-years of records were reviewed. Epilepsy prevalence and incidence were significantly associated with deprivation. Epilepsy prevalence ranged from 1.13% (1.07-1.19%) in the most deprived decile to 0.49% (0.45-0.53%) in the least deprived decile (adjusted odds ratio 0.92, p < 0.001). Epilepsy incidence ranged from 40/100,000 per year in the most deprived decile to 19/100,000 per year in the least deprived decile (adjusted incidence rate ratio 0.94, p < 0.001). There was no statistically significant change in deprivation index decile 10 years after a new diagnosis of epilepsy (mean difference -0.04, p = 0.85).

SIGNIFICANCE

Epilepsy prevalence and incidence are strongly associated with deprivation; the deprivation score remains unchanged 10 years after a diagnosis of epilepsy. These findings suggest that increasing rates of epilepsy in deprived areas are more likely explained by social causation than by social drift. The nature of the association between incident epilepsy and social deprivation needs further exploration.

Depression screening in pediatric epilepsy: evidence for the benefit of a behavioral medicine service in early detection

Despite the increased risk and prevalence of depression in youth with epilepsy, only one-third receive mental health services. Untreated depression can contribute to negative outcomes and increased health-care utilization and medical cost. Proactive behavioral medicine screening may facilitate identification of depressive symptoms and necessary interventions in efforts to optimize behavioral health and health-related quality of life (HRQOL). Primary study aims included the examination of 1) rates of self-reported depression in youth with epilepsy, 2) differences in depression by demographic and medical variables, 3) the impact of depression on HRQOL, and 4) changes in depression and suicidal ideation following a behavioral medicine consultation. As part of routine clinic care over a 24-month period, youth with epilepsy of 7-17years of age completed the Children's Depression Inventory-Second Edition. Parents completed the PedsQL. A chart review was conducted to ascertain demographics, medical variables, and behavioral medicine visits and recommendations. A subsample with Time 1 and Time 2 depression data was examined. Time 1 participants included 311 youth with epilepsy (Mage=11.9years, 50% female, 84% Caucasian, 46.0% with localization-related epilepsy, 71.0% with seizure control in the past 3months). Elevated depression was identified in 23% of youth, with 14% endorsing suicidal ideation. Depression significantly varied by age, antiepileptic drug, and insurance. After controlling for seizure status, HRQOL worsened with elevated depression. Depression significantly decreased from Time 1 to Time 2 (n=159), particularly for those referred for behavioral medicine services at Time 1. Systematic assessment and early detection of depression and/or suicidal ideation in youth with epilepsy can improve HRQOL and decrease depression. Depression screening can be implemented through clinic-based behavioral medicine services.

Demographic and social profile of epilepsy in a vulnerable low-income population in Bogotá, Colombia

INTRODUCTION

Very few studies describe the demographic and social profile of epilepsy in vulnerable low-income populations.

METHODS

Observational, descriptive, cross-sectional study prospectively recording data from all patients diagnosed with epilepsy who attended a specialist neurology consultation between January and March 2014. Data were analysed using descriptive epidemiology tools.

RESULTS

A total of 107 patients were evaluated, of whom 24.2% were illiterate and only 10.2% had completed a higher education programme. Most of the patients (86.8%) had a low socioeconomic status; 73.8% were single and 76.7% were unemployed. The main risk factors for epilepsy in this population were recorded as follows: delayed psychomotor development (n=24, 22.4%), head trauma (n=16, 14.9%), and central nervous system infection (n=13, 12.1%). Most patients (70.1%) responded to antiepileptic drugs (controlled cases) and 15.4% (n=15) had drug-resistant epilepsy (refractory cases).

CONCLUSION

The demographic and clinical profiles of the patients included in this study resemble those published for high-income populations; differences are mostly limited to aetiological classification and risk factors. The social profile of the patients evaluated in this study shows high rates of unemployment, illiteracy, and single marital status. These findings seem to be more frequent and prevalent in this group than in high income populations.

Premature mortality in poor health and low income adults with epilepsy

OBJECTIVE

To examine mortality and causes of death (CODs) in socioeconomically disadvantaged persons with epilepsy (PWEs) in the United States.

METHODS

We performed a retrospective open cohort analysis using Ohio Medicaid claims data between 1992 and 2008 to assess mortality and COD in 68,785 adult Medicaid beneficiaries with epilepsy. Case fatality (CF), mortality rates (MRs), standardized mortality ratios (SMRs), and years of potential life lost (YPLLs) were calculated. The SMRs were estimated to compare risk of death in PWEs with that in the general Medicaid population with and without disabilities. Proportionate mortality ratios (PMRs), YPLLs, and SMRs for specific COD were also obtained.

RESULTS

There were 12,630 deaths in PWEs. CF was 18.4%, the age-race-sex adjusted MR was 18.6/1,000 person-years (95% confidence interval [CI], 18.3-18.9). The SMR was 1.8 (95% CI, 1.8-1.9) when compared to the general Medicaid population, and was 1.4 (95% CI, 1.3-1.6) when compared to those with disabilities. The average YPLL was 16.9 years (range 1-47 years). Both epilepsy and comorbid conditions significantly contributed to premature mortality in PWEs. Cardiovascular diseases, cancer, and unintentional injuries were the most common COD and account for a large proportion of YPLLs. Deaths from epilepsy-related causes occurred in about 10% of the cases.

SIGNIFICANCE

Socioeconomically deprived PWEs, especially young adults, experience high mortality and die 17 years prematurely. The high mortality in Medicaid beneficiaries with epilepsy affirms that comorbid conditions and epilepsy play a crucial role in premature death. Management of comorbid conditions is, at a minimum, as important as epilepsy management, and therefore deserves more attention from physicians, particularly those who care for Medicaid beneficiaries with epilepsy.

Prevalence of epilepsy--an unknown quantity

The incidence, prevalence, and mortality of epilepsy vary across countries with different economies. Differences can be explained by methodological problems, premature mortality, seizure remission, socioeconomic factors, and stigma. Diagnostic misclassification-one possible explanation-may result from inclusion of patients with acute symptomatic or isolated unprovoked seizures. Other sources of bias include age and ethnic origin of the target population, definitions of epilepsy, retrospective versus prospective ascertainment, sources of cases, and experienced and perceived stigma. Premature mortality is an issue in low-income countries (LICs), where treatment gap, brain infections, and traumatic brain injuries are more common than in high-income countries (HICs). Death rates may reflect untreated continued seizures or inclusion of acute symptomatic seizures. Lack of compliance with antiepileptic drugs has been associated with increased risk for death, increased hospital admissions, motor vehicle accidents, and fractures in poor communities. Epilepsy is a self-remitting clinical condition in up to 50% of cases. Studies in untreated individuals from LICs have shown that the proportion of remissions overlaps that of countries where patients receive treatment. When the identification of patients is based on spontaneous reports (e.g., door-to-door surveys), patients in remission may be less likely to disclose the disease for fear of stigmatization with no concurrent benefits. This might lead to underascertainment of cases when assessing the lifetime prevalence of epilepsy. In LICs, the proportion of people living in poverty is greater than in HICs. Poverty is associated with risk factors for epilepsy, risk for developing epilepsy, and increased mortality. The high incidence and prevalence of epilepsy found in LICs is also observed in low income individuals from HICs. Epileptogenic conditions are associated with an increased mortality. This may partly explain the difference between incidence and lifetime prevalence of epilepsy in LICs. Poverty within LICs and HICs could be a preventable cause of mortality in epilepsy.

The societal integration of individuals with epilepsy: perspectives for the 21st century

Epilepsy is a common neurologic disorder seen throughout the world. Advances in therapy have made it possible for persons with epilepsy (PWEs) to have improved seizure control and a better quality of life. However, it is not entirely clear whether this has resulted in their successful integration into society. This review examines the societal integration of PWEs, identifying both the progress made and the challenges that continue to hamper further advances. In general, PWEs are more integrated in western-oriented cultures. However, there continue to be ongoing difficulties due to poor education and intellectual functioning, poor social and family support, the undertreatment of coexisting psychiatric conditions, transportation and mobility limitations, and problems obtaining employment. This review also discusses the effects of low socioeconomic status on integration and the persisting prejudices that affect certain racial groups. Most importantly, this review underscores the fact that societal stigma towards PWEs is still very much alive. At the beginning of the 21st century, PWEs still encounter difficulties in their quest for full societal integration. Along with medical advances being made to improve seizure control, much still has to be done to bring about the reforms necessary to help PWEs live more meaningful and productive lives.

Adherence to medication among outpatient adolescents with epilepsy

BACKGROUND AND OBJECTIVE

The promotion of medication adherence is considered as an integral component of pharmaceutical care practice and patient healthcare. An approach which focuses on the choice and dose of antiepileptic drug will have limited success without medication adherence. This study sought to assess medication adherence for improvement among adolescents who are suffering from epilepsy.

METHODS

A total of 116 patients affected with idiopathic epilepsy and fulfilled the inclusion criteria were recruited in the current study. Adherence to the treatment was evaluated during patients' hospitalization in the Department of Neurology at Riyadh National Hospital, Riyadh, Saudi Arabia, between December 2011 and January 2014. The medication adherence has been assessed during semi-structured interviews with each patient and/or his parents using a multiple choice graded questionnaire.

RESULTS

From the selected group of patients, only 94 patients (81.0%) fulfilled the inclusion criteria within the study period. Thirty-six of respondents (38.3%) were non adherent to antiepileptic treatment. No statistical differences were found between males and females regarding their ages, age at diagnosis of epilepsy, mother age, epilepsy duration, family numbers, number of poor-adherents or seizure frequency. The most important factors that were significantly affecting patients' adherence to the prescribed medications were age of mother, family number, number of administered drugs, the stability of parents' marriage, family support, and seizure frequency as well as the regularity of the relationship between patients and their healthcare providers. Forgetfulness was the most common cause of non-adherence among this group of patients followed by inability to obtain medication and fear from side effects of drugs. Our results revealed also that the number of patients who felt to be stigmatized is significantly more in non-adherent group as compared to patients with a strong sense of normality (P < 0.05). A positive relationship between adherence and the necessity and benefit scales at which patients have a stronger belief in the necessity of medication for controlling illness was associated with good adherence.

CONCLUSION

The assessment of medication adherence among epileptic patients should be a routine part of the management process to improve the health care and quality of lives of those patients.

Defining incident cases of epilepsy in administrative data

PURPOSE

To determine the minimum enrollment duration for identifying incident cases of epilepsy in administrative data.

METHODS

We performed a retrospective dynamic cohort study using Ohio Medicaid data from 1992 to 2006 to identify a total of 5037 incident epilepsy cases who had at least 1 year of follow-up prior to epilepsy diagnosis (epilepsy-free interval). The incidence for epilepsy-free intervals from 1 to 8 years, overall and stratified by pre-existing disability status, was examined. The graphical approach between the slopes of incidence estimates and the epilepsy-free intervals was used to identify the minimum epilepsy-free interval that minimized misclassification of prevalent as incident epilepsy cases.

RESULTS

As the length of epilepsy-free interval increased, the incidence rates decreased. A graphical plot showed that the decline in incidence of epilepsy became nearly flat beyond the third epilepsy-free interval.

CONCLUSION

The minimum of 3-year epilepsy-free interval is needed to differentiate incident from prevalent cases in administrative data. Shorter or longer epilepsy-free intervals could result in over- or under-estimation of epilepsy incidence.