Underlying cause of death in incident unprovoked seizures in the urban community of Northern Manhattan, New York City

We determined underlying cause-specific mortality for incident unprovoked seizures from Northern Manhattan, New York City. We calculated the case fatality, proportionate mortality, and the underlying cause-specific standardized mortality ratios (SMRs), with U.S. death rates as the standard. Thirty-two deaths were observed between 2003 and 2007 among 209 participants. Case fatality was significantly lower for idiopathic/cryptogenic seizures versus symptomatic seizures. About 31.3% of the deaths were attributed to malignant neoplasms, 25.0% to diseases of the heart, 15.6% to influenza and pneumonia, 3.1% to cerebrovascular diseases, and 25.0% to other causes. Significant SMRs were observed for all causes (SMR = 1.6), influenza and pneumonia (SMR = 7.1), and malignant neoplasms (SMR = 2.9). Younger cases (<65 years) had increased SMRs for all causes, malignant neoplasms, and other causes. Older cases (≥65 years) had increased SMRs for influenza and pneumonia. Underlying cause of death paralleled the underlying cause of seizure in patients with symptomatic etiologies.     

The incidence of epilepsy and unprovoked seizures in multiethnic, urban health maintenance organizations

PURPOSE: Studies of the incidence of epilepsy are limited to a few populations in which new cases can be ascertained. Health maintenance organization (HmO) populations were studied to determine the incidence in a multiethnic, urban United States population. METHODS: Cases of initial unprovoked seizure disorder or epilepsy while enrolled in an HMO between 1988 and 1994 were ascertained. Ethnicity was obtained from the medical records and was part of a nested case-control study. RESULTS: There were 197 incidence cases of epilepsy and 275 of initial unprovoked seizure diagnosis. The incidence rate in the age range 0-64 years was 35.5 per 100,000 for epilepsy and 50.9 for initial unprovoked seizure. When compared with population-based studies, rates were slightly higher in children younger than 15, similar for the 15- to 24-year age group, but lower for ages 25-64 years. The ethnicity-specific odds ratios for initial unprovoked seizure, by using non-Hispanic white as the referent, were 1.04 (0.73-1.49) for African-American, 0.97 (0.64-1.48) for Hispanic, and 0.25 (0.08-0.84) for Asian-American. CONCLUSIONS: The lower rate in the HMO population is presumably due to a healthy-worker effect. The ethnicity-specific incidence rates do not differ in this population.     

Newly diagnosed single unprovoked seizures and epilepsy in Stockholm, Sweden: First report from the Stockholm Incidence Registry of Epilepsy (SIRE)

Purpose:   To describe and report initial findings of a system for prospective identification and follow-up of patients with newly diagnosed single unprovoked seizures and epilepsy in Stockholm, Sweden, the Stockholm Incidence Registry of Epilepsy (SIRE).
Methods:   From September 2001 through August 2004, a surveillance system has been in use to identify incident cases of first unprovoked seizures (neonatal seizures excluded) and epilepsy among residents of Northern Stockholm, an urban area with approximately 998,500 inhabitants. Potential cases are identified through multiple mechanisms: Network of health care professionals, medical record screening in specific hospital units, including outpatient clinics, emergency room services, and review of requests for electroencephalography (EEG) examination. Potential cases are classified 6 months after the index seizure based on review of medical records.
Results:   After screening approximately 10,500 EEG requests and 3,300 medical records, 1,015 persons met the criteria for newly diagnosed unprovoked seizures (430 single seizures; 585 epilepsy). The crude incidence for first unprovoked seizures and epilepsy was 33.9/100,000 person years, (the same adjusted to the European Standard Million), highest the first year of life (77.1/100,000) and in the elderly. No cause could be identified in 62.4%.
Conclusions:   We have established a sustainable system for prospective identification of new onset epilepsy cases in Stockholm. Despite a possible under-ascertainment, the registry provides a useful starting point for follow-up studies.     

Systematic review and meta-analysis of incidence studies of epilepsy and unprovoked seizures

PURPOSE: To evaluate the methodology of incidence studies of epilepsy and unprovoked seizures and to assess the value of their findings by summarizing their results. METHODS: A Medline literature search from January 1966 to December 1999 was conducted. In each selected study, key methodologic items such as case definition and study design were evaluated. Furthermore, a quantitative meta-analysis of the incidence data was performed. RESULTS: Forty incidence studies met the inclusion criteria. There was considerable heterogeneity in study methodology, and the methodologic quality score was generally low. The median incidence rate of epilepsy and unprovoked seizures was 47.4 and 56 per 100,000, respectively. The age-specific incidence of epilepsy was high in those aged 60 years or older, but was highest in childhood. Males had a slightly higher incidence of epilepsy (median, 50.7/100,000) than did females (median, 46.2/100,000), and partial seizures seemed to occur more often than generalized seizures. Developing countries had a higher incidence rate of epilepsy (median, 68.7/100,000) than did industrialized countries (median, 43.4/100,000). Similar results were found for unprovoked seizures. The incidence of epilepsy over time appears to decrease in children, whereas it increases in the elderly. CONCLUSIONS: The age-specific incidence of epilepsy showed a bimodal distribution with the highest peak in childhood. No definitive conclusions could be reached for the incidence of unprovoked seizures and other specific incidence rates of epilepsy. More incidence studies with an adequate study methodology are needed to explore geographic variations and time trends of the incidence of epilepsy and unprovoked seizures.     

Seizure recurrence after a first unprovoked seizure in childhood: a prospective study

PURPOSE: To study the risk of recurrence after a first unprovoked seizure in childhood. METHODS: All consecutive patients aged less than 14 years with one or more unprovoked seizures who were attended between January 1, 1987, and June 1, 1996, were included in a prospective study. Clinical features of patients attended after a first seizure and those attended after two or more seizures were compared. Recurrence risk in both groups was estimated by Kaplan-Meier curves. Univariate and multivariate analyses of the potential predictors of recurrence risk were performed for the group of patients attended after a first seizure using the Cox proportional hazards model. RESULTS: Included in the study were 217 children. Kaplan-Meier estimate of recurrence risk was 64% at 5 years, when only patients being attended after a first epileptic seizure were included, compared with 74% when all patients were included. Significant differences in several clinical features were found between patients attended after a first seizure and those attended after two or more seizures. Univariate and multivariate analyses showed that in the overall cohort of patients attended after a first seizure, a symptomatic etiology increased the risk of recurrence, whereas a patient age of 3 to 10 years decreased this risk. In particular, the recurrence risk was 96% at 2 years for symptomatic seizures, compared with 46% for idiopathic/cryptogenic seizures. In the group of patients with idiopathic/cryptogenic seizures, an abnormal electroencephalogram and the occurrence of seizures during sleep increased the recurrence risk, whereas a patient aged 3 to 10 years reduced it. In the group of patients with symptomatic etiology, univariate analysis revealed that there was a lower recurrence risk for patients aged 3 to 10 years. This last finding was not maintained, however, in multivariate analysis. CONCLUSIONS: The recurrence risk depends on the inclusion criteria for enrolling patients. Several factors enable us to predict the recurrence risk after a first unprovoked seizure; the most important of these factors is the etiology of the seizures.     

Episousse: incidence of newly presenting seizures in children in the Region of Sousse, Tunisia

PURPOSE: To evaluate the incidence of newly presenting seizures in children in the area of Sousse, Tunisia. METHODS: From June 1, 1998, to May 31, 1999, all children aged 1 month to 15 years with first provoked and unprovoked seizures were included. Children with febrile seizures were excluded. All suspected cases were systematically referred to the Department of Functional Explorations of the Nervous System where a detailed questionnaire was filled out by a neurologist. All the patients underwent an EEG. Only 12 patients had a computed tomography (CT) scan. RESULTS: A total of 175 patients were included. Eighteen (10.3%) patients had acute symptomatic seizures, and 157 patients had unprovoked seizures. The incidence rate of first unprovoked seizures was 102.1/100,000. In this latter group, some epileptic syndromes were individualized on strict electroclinical criteria. CONCLUSIONS: However, nearly 75% of the cases remained cryptogenic, one of the major reasons that no predominant risk factor was identified in this population.     

The incidence of first provoked and unprovoked seizure in pediatric patients with and without psychiatric diagnoses

PURPOSE: To estimate the rate of new-onset afebrile provoked and unprovoked seizure in a general pediatric population and subgroups of patients with and without psychiatric diagnoses other than attention deficit hyperactivity disorder (ADHD). METHODS: A retrospective cohort study of 133,440 pediatric patients, between the ages of 6 and 17 years, and without history of seizure or prior use of anticonvulsant medications, with follow-up during 2003. The data source for this study was Ingenix's research database containing pharmacy and medical claims for members of a large US-based managed care organization. The main outcome measure was new-onset nonfebrile seizure. Incidence rates of seizure and 95% confidence intervals (CI) were calculated and expressed as rates per 100,000 person-years. RESULTS: There were 132 new-onset provoked and unprovoked seizures in 78,423 person-years of follow-up among the general pediatric population sample. The incidence rate of seizure among the general pediatric population was 168 per 100,000 p-y (95% CI 141-200). The incidence rate of seizure among patients without psychiatric diagnoses was 149 per 100,000 p-y (95% CI 122-180). The incidence rate of seizure among patients with psychiatric diagnoses other than ADHD was 513 per 100,000 p-y (95% CI 273-878). There were increases in the incidence rates of seizure in all of the seizure risk factor groups, but this was more pronounced among males ages 6-12 with psychiatric diagnoses. CONCLUSIONS: The results of this study are consistent with previous reports showing that pediatric patients with psychiatric disorders have a higher incidence rate of seizure than the general pediatric population.     

Socioeconomic prognosis after a newly diagnosed unprovoked epileptic seizure in adults: a population-based case-control study

PURPOSE: To investigate the socioeconomic prognosis after a newly diagnosed unprovoked epileptic seizure in adults. METHODS: Sixty-three patients 17 years or older with a newly diagnosed unprovoked epileptic seizure from 1985 through 1987 and 107 sex- and age- matched controls were followed up for 10 years to 1996. Studied variables were income, source of income, sickness periods, incapacity rate, diagnosis-specific incapacity rate, vocational status, and education. RESULTS: Relative growth of income was similar between patients and controls during follow-up. Patients had lower income than did controls 2 years before seizure onset and during the entire follow-up. This was related to higher morbidity among patients, as measured by sickness periods and incapacity rate. Employment rates did not evolve negatively among patients after seizure onset and were close to employment rates of controls during follow-up time. There was no difference between patients and controls regarding education. CONCLUSIONS: After a newly diagnosed unprovoked epileptic seizure in adults, no negative development regarding employment and education occurs. Income development is positive unless refractory seizures evolve. However, income is lower among patients with epilepsy than among controls, and this difference can be related to overall morbidity.     

A population‐based study of newly diagnosed epilepsy in infants

Purpose: Most published data on infants presenting with epilepsy originate from hospital/specialist clinic settings and may therefore not be representative of the general population. We carried out a population‐based study to estimate the incidence of epilepsy onset in infants, to characterize the range of phenotypes and associated structural brain abnormalities, and to determine whether specific epilepsy diagnoses could be established at onset. Methods: Children between 1 and 24 months of age with new‐onset epilepsy were ascertained over 13 months from the residents in 15 boroughs of North London. Classification based on clinical information, electroencephalography (EEG), and neuroimaging data was undertaken independently by two pediatric neurologists. Neuroimages were reviewed by two neuroradiologists blinded to clinical details. Key Findings: A total of 57 children were enrolled giving an ascertainment‐adjusted incidence of 70.1 (95% CI [56.3, 88.5])/100,000 children ≤2 years of age/year (ascertainment 76%). The incidence was highest among Asian children. An electroclinical syndrome was identified in 24 (42%) cases of which 21 were epileptic encephalopathies. Magnetic resonance (MR) images of 51 cases (89% of the total cohort) were reviewed. These demonstrated positive findings in 37 (72%) of 51 cases, of which 26 (51%) of 51 were etiologically relevant, and included developmental malformations in 11 (21%) of 51. Significance: In a population setting infantile onset epilepsy presents mostly with complex phenotypes commonly associated with structural brain abnormalities. Routine MR imaging at presentation is therefore justified. However, identification of specific electroclinical syndromes remains difficult at onset.     

The incidence of epilepsy in a rural district of Vietnam: A community‐based epidemiologic study

Purpose: Epidemiologic studies of epilepsy from developing countries are scarce. As part of a population‐based epidemiologic project in Vietnam, EPIBAVI, we studied the incidence and etiology of epilepsy in people in a representative rural region of the country. Methods: Two identical field surveys were carried out 3 years apart (January to December 2005, and June to December 2008) in the same population of the Bavi District in Vietnam. On both occasions, close to 50,000 members of approximately 13,000 households were screened using a questionnaire for epilepsy. A clinical examination of all screened positive was performed by a neurologist to verify the epilepsy diagnosis, and all incident cases were offered EEG and a CT scan. Results: In the first survey 2.8% screened positive according to the questionnaire. Of these, 19 had epilepsy onset within 1 year preceding the screening, yielding an incidence rate of 40.2 per 100,000 [95% confidence interval (CI) 22.1–58.3]. In the second survey 1.8% were screened positive, and 21 of these had epilepsy onset within 1 year preceding the screening, giving an incidence rate of 42.9 per 100,000 (95% CI 24.5–61.2). The age‐adjusted incidence was 44.8 per 100,000 (95% CI 30.6–59.0). The incidence was higher in those younger than 16 years, among people with lower education, and among people with lower income. CT scan was performed in 29 cases and only two cases were found with some abnormalities. Discussion: The incidence rate of epilepsy in rural Vietnam in our study was lower than in developing countries in Latin America and Africa and similar to rates in Europe and North America.     

Estimating prevalence, incidence, and disease-related mortality for patients with epilepsy in managed care organizations

PURPOSE: The purpose of the present study was to apply computer algorithms to an administrative data set to identify the prevalence of epilepsy, incidence of epilepsy, and epilepsy-related mortality of patients in a managed care organization (MCO). METHODS: The study population consisted of members enrolled in Lovelace Health Plan, a component of Lovelace Health Systems, a statewide MCO headquartered in Albuquerque, New Mexico. Patient records were obtained from July 1996 to June 2001. Four logistic regression models with high sensitivity and specificity were applied to 1-, 3-, and 5-year time frames in which members were continuously enrolled in the MCO. Incidence was defined for patients who did not have an epilepsy-associated code in the 18 months before the first diagnosis entry. Mortality estimates in the population also were assessed by using a matched control group and linkage to a statewide death registry. RESULTS: The data yielded estimated prevalence rates of 7-10 per 1,000, depending on age, sex, ethnicity, and time interval. Annualized incidence was 47 per 100,000 for members continuously enrolled for 3 years and 71 per 100,000 for members continuously enrolled for 5 years. Crude mortality rates were 2-2.5 times higher for epilepsy patients identified with the algorithms than for the matched controls. Conditional logistic regression indicated that the odds of death for epilepsy patients as compared with controls ranged from 1.24 to 2.06. CONCLUSIONS: Accurate estimation of prevalence, incidence, and mortality rates for epilepsy is an essential component of disease management in MCOs. The algorithms in this project can be used to monitor trends in prevalence, incidence, and mortality to inform decisions critical to improving the health care needs and quality of life for patients with epilepsy.     

Geographic variation in the age- and gender-specific prevalence and incidence of epilepsy: analysis of Taiwanese National Health Insurance-based data

Purpose: We studied geographic variation in age‐ and gender‐specific prevalence and incidence of epilepsy in four different areas of Taiwan. Methods: By using large‐scale, National Health Insurance (NHI)–based data from 2000–2003 in Taiwan, we identified 131,287 patients diagnosed with epilepsy (ICD code 345) receiving at least of one of 11 antiepileptic drugs (AEDs). Information on age, gender, and location were also collected. The multivariable Poisson regression analysis was used to assess the heterogeneity of the morbidity of epilepsy in different regions. External data validation was also performed to assess the accuracy of capturing epilepsy cases through our NHI data set. Key Findings: The age‐adjusted prevalence and incidence of epilepsy were 5.85 (per 1,000) between 2000 and 2003 and 97 (per 100,000 person‐years) during the follow‐up time from 2001 to 2003 in Taiwan. The sensitivity and specificity of ICD‐9 coding for epilepsy in the NHI data set were 83.91% and 99.83%, respectively, resulting in a slight overestimation. Male patients had a higher probability of having epilepsy than did females. East Taiwan had significantly higher prevalence and incidence than did other areas. The age‐specific incidence pattern in east Taiwan was atypical in that it revealed clustering in young and middle‐aged groups. Significance: Our study demonstrated geographic variation in epidemiologic patterns of epilepsy within Taiwan. The findings are informative and provide insight into the clinical management of epilepsy based on consideration of different target groups in different areas.     

Risk of recurrence after first unprovoked tonic-clonic seizure in adults

The likelihood of seizure recurrence after a first unprovoked seizure has profound social, vocational and emotional implications for the patients. Recurrence rates have varied between 27% and 71% in various studies, and the management of patients with a single unprovoked seizure is a controversial topic. In this prospective study we investigated the influence of age, sex, family history, EEG patterns, and anticonvulsant drug (ACD) therapy on seizure recurrence after a first unprovoked tonic-clonic seizure in adults. For this purpose, between October 1988 and January 1991, we studied adult patients who had experienced their after unprovoked tonic-clonic seizure within last 2 months before neurological consultation, and followed them until June 1993. There were 147 patients who met the criteria for inclusion. Overall cumulative recurrence rates were 31.8% by 6 months, 41.3% by 1 year, 44.1% by 2 years, 42.2% by 3 years, and 45.2% by 4 years. Among the risk factors that were evaluated, the time of the day at which the initial seizure occurred was associated significantly (P < 0.05) with seizure recurrence. In our series, 62 patients received ACD and 85 did not. We did not find a significant difference in recurrence rate with regard to ACID therapy. Our results are comparable with those of studies reported preeviously and suggest that the majority of recurrences after a first unprovoked seizure were seen in the first year (in our series 89% of all recurrences). In our study there was no significant predictor of seizure recurrence, except the time of day at which the initial seizure occurred.Presented in part at the XVth World Congress of Neurology, Vancouver, Canada, 5–10 September 1993     

Mortality risk in an adult cohort with a newly diagnosed unprovoked epileptic seizure: a population-based study

PURPOSE: We sought to investigate mortality risk in an adult cohort with newly diagnosed unprovoked epileptic seizures. METHODS: One hundred seven patients who were at least 17 years old and had newly diagnosed unprovoked epileptic seizures were prospectively identified during a period of 20 months between 1985 and 1987. Patients were followed until the date of death or the end of 1996. The standard mortality ratio (SMR) was analyzed in the whole cohort and in the portion of the cohort with recurrent seizures at inclusion. The influences on the SMR of time since diagnosis, sex, age at diagnosis, seizure cause, seizure type, and cause of death were also investigated. RESULTS: The SMR was significantly increased (SMR, 2.5; 95% confidence interval [CI], 1. 2-3.2). This significantly increased risk was found during the first 2 years after diagnosis (year 1: SMR, 7.3; 95% CI, 4.4-12.1; year 2: SMR, 3.6; 95% CI, 1.6-8.1) and at years 9-11 (SMR, 5.4; 95% CI, 2. 7-11.2). The increased mortality risk was most pronounced when the seizures occurred before the age of 60 years. Mortality risk was elevated among patients with remote symptomatic epilepsy (SMR, 3.3; 95% CI, 2.4-4.5) but not idiopathic epilepsy. CONCLUSIONS: There is increased mortality risk in an adult cohort with newly diagnosed unprovoked epileptic seizures. This increase is found in symptomatic patients, young patients, and during the first 2 years after the diagnosis.