Epilepsy: People With Multiple Sclerosis May Be at High Risk

Multiple sclerosis (MS) is an independent risk factor for both incident and prevalent epilepsy, according to a systematic review and meta-analysis. The findings were published in Multiple Sclerosis and Related Disorders.

MS is the most common inflammatory demyelinating disease of the central nervous system. Approximately 2.2 million people worldwide live with this condition, according to a 2016 report.

The study evaluated the prevalence or incidence of epilepsy in adults with MS. While previous studies found the prevalence and incidence of epilepsy was higher among people with MS compared with the general population, it has remained unclear if MS is independently associated with epilepsy.

Using data collected from inception of MEDLINE and Embase to July 1, 2022, the researchers included a total of 17 observational studies consisting of 192,850 adults (³ 18 years) with MS across 9 different countries. Among these studies, 70% of participants were women (n = 10 studies), and the average age was 45.6 years (n = 6).

The studies were all conducted between 1999 and 2021 with 13 conducted in Europe and 4 in North America. The majority of studies (n = 10) reported prevalence of epilepsy with 3 studies reporting incidence and 4 studies reporting both. Nearly all (n = 15) studies were retrospective cohort designs with 2 studies being case controls.

These studies observed the prevalence or incidence of epilepsy in adults with MS, and a comparator group, which consisted of adults without MS, or a general population group.

Results of these studies found that people with MS were twice more likely to have prevalent epilepsy compared to their comparison groups.

In comparison to the group without MS, both the prevalence (pooled odds ratio 2.04; 95% CI 1.59-2.63, I2 = 95.4, n = 12), and incidence of epilepsy (pooled risk ratio 3.34; 95% CI 3.17-3.52, I = 4.6%, n = 6), was higher in people with MS.

“Subgroup and meta-regression showed that our results were consistent, and the heterogeneity remained unexplained,” the authors noted. In addition, when only analyzing high-quality studies that did not have an overlap in study populations, the researchers found the association between MS and prevalent epilepsy moved closer to null.

Given the greater association between MS and incident epilepsy, compared with MS and prevalent epilepsy, the findings suggest a variation in grey matter involvement over the disease course, according to the authors.

“The quality of included studies was moderate as many studies did not exclude those with epilepsy at the start of the study and those with risk factors for epilepsy,” noted the authors. “Furthermore, the definitions of MS and epilepsy were variable across different studies, and so were the methods used to ascertain epilepsy and MS diagnoses, possibly leading to the observed high heterogeneity.”

Among the additional limitations to the study was the lack of information regarding MS disease subtype, disease severity, treatments, or seizure type. Without this information, the authors were not able to provide a more detailed assessment of seizure risk factors.

They believe that additional studies may help to identify patient disease characteristics that are associated with epilepsy, as well as improve screening and treatment to reduce the burden of epilepsy in these higher risk populations.

“Knowing that comorbid epilepsy may affect clinical course of MS, future studies should help identify patients with MS who are at risk of epilepsy to improve screening and treatment and in turn reduce the burden of epilepsy in this population,” wrote the authors.

Reference

Kuntz S, Wu AS, Matheson E, Vyas I, Vyas MV. Association between multiple sclerosis and epilepsy: A systematic review and meta-analysis. Multiple Sclerosis and Related Disorders. 2022:104421. doi:10.1016/j.msard.2022.104421