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.


CONCLUSIONS
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.
Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.
Sandra L
SL
Helmers
Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.
David J
DJ
Thurman
UCB Pharma, Smyrna, Georgia, U.S.A.
Tracy L
TL
Durgin
Department of Biostatistics and Bioinformatics, Emory University School of Medicine, Atlanta, Georgia, U.S.A.
Akshatha Kalsanka
AK
Pai
Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.
Edward
E
Faught
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual / Q000706:statistics & numerical data; D004827:Epilepsy / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007348:Insurance, Health / Q000706:statistics & numerical data; D008297:Male; D008484:Medicaid / Q000706:statistics & numerical data; D008875:Middle Aged; D019370:Observation; D015995:Prevalence; D014481:United States / Q000453:epidemiology; D055815:Young Adult
Cohort studies; Epidemiology; Epilepsy; Incidence; Prevalence