One in 26 Americans Will Develop Epilepsy

Allison Gandey

January 07, 2011

January 7, 2011 — An estimated 1 in 26 Americans will develop epilepsy in their lifetime, a risk that translates to about 12 million people in the United States, report researchers. This number is much higher than current estimates by the Centers for Disease Control and Prevention (CDC) that suggest roughly 2 million people in the United States currently have epilepsy.

The CDC reports the total indirect and direct cost of epilepsy in the United States is more than $15.5 billion. The authors of this new report, published in the January 4 issue of Neurology, suggest this amount could increase in years to come.

"Our results highlight the need for more research using epilepsy surveillance data, especially given the aging population in the United States," lead investigator Dale Hesdorffer, PhD, from Columbia University in New York, said in a news release. "Such surveillance will also provide useful information for healthcare planners as they address the service needs of people with epilepsy."

As expected, the elderly had the highest incidence.

Previous studies assessing the risk for epilepsy have failed to account for the competing risk for death, note researchers. This is an important flaw when considering elderly patients, where the rate of epilepsy is highest. "We report the lifetime risk for epilepsy, accounting for mortality," they explain.

The investigators assessed lifetime risk and cumulative incidence of epilepsy among residents of Rochester, Minnesota. They identified 412 people with incident epilepsy diagnosed between 1960 and 1979.

The researchers saw similar differences across epilepsy etiologies. Men had a higher risk of developing epilepsy, with a rate of 1 of every 21 males.

Lifetime risk through 87 years of age increased over time from 3.5% in the 1960s to 4.2% in the 1970s.

"These authors should be commended for their sophisticated analysis, which is an important contribution to the epilepsy epidemiology research literature," Edwin Trevathan, MD, from Saint Louis University in Missouri, said in an accompanying editorial.

Inadequate Surveillance Infrastructure

However, the study has important limitations, Dr. Trevathan points out. "Their analysis is of people whose epilepsy was diagnosed 31 to 50 years ago. Timely, good-quality population-based data that met their research needs were not available. The study authors did the best analysis possible with the data available, but these data from a long-past era of epilepsy classification, diagnosis, and care may not reflect the current reality of neurology practice."

Dr. Hesdorffer told Medscape Medical News he agrees the findings may not reflect current lifetime risk. "Life expectancy has increased over time," he pointed out, "current lifetime risk would be greater than what we observed."

Flying blind.

Dr. Trevathan says this issue is a manifestation of a much greater problem. He points to an almost absent epilepsy surveillance infrastructure in the United States.

"The need for a coordinated public health response to epilepsy is now being addressed by some of our public health leaders, and it is hoped that this will soon be the topic of serious study with recommendations for improvement," he notes.

"Epilepsy is a common, serious neurologic disorder with a major impact on public health and therefore deserves the best public health response directed by timely high-quality surveillance data," Dr. Trevathan points out. "Until we have good national epilepsy surveillance data informing our direction, public health authorities must do their best to help people with epilepsy while flying blind."

This study was funded by the National Institute for Neurologic Disorders and Stroke and the National Institutes of Health. Dr. Hesdorffer has served on a scientific advisory board for Pfizer and has received funding for travel from UCB. Editorialist Dr. Trevathan serves on the editorial boards of Neurology, Disability and Health Journal, and TheJournal of Developmental Origins of Health and Disease.

Neurology. 2011;76:23-27.


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