Epilepsy Risk Factors in the Elderly

April 20, 2016

Researchers studied the prevalence and incidence of epilepsy in the elderly and confirmed three risk factors in this patient population.

Past studies have determined the prevalence and incidence of epilepsy among the elderly, but few have incorporated racial, socioeconomic, or geographical data in their studies to assess the risk of incident epilepsy.

According to Hyunmi Choi, the presenter of this study at the American Academy of Neurology’s 68th annual meeting in Vancouver, discussion of epilepsy among the elderly is important for four reasons:

1. A high number of all new seizures are seen in older adults. A cohort study in the UK showed 24% of new cases are seen in adults over 60.

2. Causes of clinical manifestation among older people differs from that among younger people, which can undermine our ability to diagnose epilepsy accurately.

3. Treatment issues are more complicated among older people due to physiological, age-related changes that can lead to pharmacokinetic or pharmacodynamic changes.

4. The elderly are already vulnerable to a diminished quality of life (QOL). With epilepsy they can have further loss of independence, partly due to driving restrictions, risk of falling, and so on.

To prevent extreme loss in the QOL among the elderly who have epilepsy, we need the ability to identify it. Diagnosis never comes easy, but among this age group the waters become even more murky.

We know that symptoms typically seen in younger people are less common among the elderly. Automatisms, for instance, do not commonly occur and auras are less common.  This can lead to difficulty in identifying epilepsy among older adults. As an example, Study V28 shows that epilepsy was not considered in nearly half of the patients who later had seizures.

Significantly, there have not been many studies incorporating African American subjects. Yet race may pose a significant risk for epilepsy. This study, thus, looks at race as a risk factor for the incidence of epilepsy among the elderly. 

The research team comprised of Hyunmi Choi, Alison Pack, Mitchel Elkind, T. Longstreth, and Franklin Onchiri performed a secondary data analysis, pulling data from two sources:

1. data collected in the Cardiovascular Health Study (CHS)

2. data from outpatient Medicare claims. They used ICD-9 codes to identify epilepsy among the claimants.

“Prior studies that had used administrative claims,” reports Choi, “had suggested that positive predictive value of identifying epilepsy cases goes up when you use outpatient claims data merged with additional clinical data such as medication history.”

The results confirmed the team’s expectation that epilepsy among the elderly is common. It also confirmed three risk factors associated with incident epilepsy are:

• Race: African Americans are significantly more at risk than Caucasians (4.2 vs 2.1 per 1000 person years).

• Self-perceived health: those who developed epilepsy had reported “poor” health at the outset of the study; those with “excellent” health were epilepsy free.

• Education: those with post-secondary education had a range of 45% to 53% less chance of developing epilepsy. 

Finally, QOL declines as people age. The more accurately we can identify epilepsy among the elderly, the less dramatic that decline.

From materials presented during AAN Annual Meeting in Vancouver, British Columbia. Session S14: Epilepsy: Antiepileptic Drugs and Epidemiology. Apr 17, 2016.