Estimating the Prevalence of Treated Epilepsy Using Administrative Health Data and Its Validity: ESSENCE Study.
OBJECTIVE
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.
Department of Neurology, Kangwon National University College of Medicine, Chuncheon, Korea.
Seo Young
SY
Lee
Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea.
Soo Eun
SE
Chung
Department of Neurology, Konkuk University, School of Medicine, Seoul, Korea.
Dong Wook
DW
Kim
Department of Pediatrics, Korea University College of Medicine, Ansan, Korea.
So Hee
SH
Eun
Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea.
Hoon Chul
HC
Kang
Department of Neurology, Keimyung University School of Medicine, Daegu, Korea.
Yong Won
YW
Cho
YiSangDo Neurology Clinic, Daegu, Korea.
Sang Do
SD
Yi
Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea.
Heung Dong
HD
Kim
Department of Neurology, Seoul National University College of Medicine, Seoul, Korea. jungky@snu.ac.kr.
Ki Young
KY
Jung
Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea. hkcheong@skku.edu.
Hae Kwan
HK
Cheong
epidemiology; epilepsy; health data; prevalence; seizure; validation