Prevalence of epilepsy in rural Kansas

To determine the prevalence of active epilepsy in two southeastern rural Kansas counties.

Medical records were abstracted from the emergency rooms, out- and inpatient services and clinics of 9 hospitals, from 10 doctors' offices, and 1 nursing home in and surrounding the two counties. Letters were mailed from hospitals and doctors' offices to invite their potentially eligible patients to participate in an interview. Medical record information and the interview, when available, were used for the final determination of active epilepsy, seizure type, etiology, syndrome, age, and gender in consensus conferences. Prevalence of epilepsy was calculated, and capture-recapture methodology, which estimates prevalence based on what is known about the population, was employed to assess active epilepsy in the two counties.

This study identified 404 individuals with active prevalent epilepsy who visited at least one of the 20 facilities during the observation period. The overall prevalence of active epilepsy was 7.2 per 1000. The seizure type for 71.3% of prevalent cases was unknown; among the 76 cases with known and classifiable seizure type, 55.3% had focal with secondary generalized seizures. Among the 222 cases with classifiable etiology, 53.1% were idiopathic/cryptogenic. About 75% (n=301) were captured at only one center, 72% (n=75) of the remaining 103 patients were captured at two centers, and 28 patients were identified at three or more centers. The capture-recapture assessment yielded an estimation of 982 prevalent patients. The overall estimated prevalence of epilepsy in the two Kansas counties using capture-recapture was 17 per 1000.

The crude prevalence of epilepsy, using medical record survey methods, was similar to, but on the high end, of other total population prevalence studies in the United States. The capture-recapture assessment suggested that epilepsy prevalence might be considerably higher than the crude prevalence.