J Clin Neurol.  2016 Oct;12(4):434-440. 10.3988/jcn.2016.12.4.434.

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

• Lee SY
• Chung SE
• Kim DW
• Eun SH
• Kang HC
• Cho YW
• Yi SD
• Kim HD
• Jung KY
• Cheong HK
• Committee on Epidemiology of Korean Epilepsy Society

• KMID: 2385107
• DOI: http://doi.org/10.3988/jcn.2016.12.4.434

Abstract

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.

Keyword

epilepsy; seizure; prevalence; health data; epidemiology; validation

MeSH Terms

Aged
Anticonvulsants
Asian Continental Ancestry Group
Child
Epidemiologic Studies
Epidemiology
Epilepsy*
Female
Humans
Insurance, Health
Korea
Male
Medical Records
Methods
Prescriptions
Prevalence*
Referral and Consultation
Seizures
Anticonvulsants

Figure

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  Fig. 1 Study design. AEDs: antiepileptic drugs, HIRA: Health Insurance Review and Assessment service.

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  Fig. 2 Prevalence of treated epilepsy according to age group and sex. The prevalence was higher in males than in females for all age groups except patients aged 1–9 years. The prevalence was relatively constant across age groups, although with a tendency to be higher in patients younger than 15 years of age and the elderly.

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  Fig. 3 Age- and sex-specific prevalence of treated epilepsy in patients with and without diagnostic codes indicating epilepsy or seizure (Diagnosis-E). The curves appeared as an inverted U-shape peaking at adolescence for patients with Diagnosis-E, and as an upright U-shape for the group without Diagnosis-E. M: males, F: females.

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