In addition to high rates of anxiety and mood disorders, epilepsy is associated with several comorbidities including headache, hypertension, and back pain, new research shows. Investigators also found racial and ethnic disparities in comorbidity prevalence.

“Our study identified that people with epilepsy have complex healthcare needs that extend well beyond their epilepsy,” co-investigator Wyatt P. Bensken, PhD candidate, Department of Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, Ohio, told Medscape Medical News.

The findings were presented at the American Epilepsy Society (AES) 2021 Annual Meeting.

Researchers identified individuals with epilepsy using Medicaid claims from 2010 to 2014. Bensken noted that the approximately one third of patients with epilepsy covered by Medicaid represent “the most vulnerable” population with the disorder because they may not be working and often have other disabilities.

Based on an algorithm that puts diagnostic codes into clinically meaningful categories, the investigators focused on 190 conditions.

“A strength of the study was that we were able to cast such a broad net” to capture conditions, Bensken said.

Anxiety and mood disorders were originally in separate categories but were grouped together “after recognizing that those who had one pretty much had the other,” he added.

The researchers used a machine learning technique known as association rule mining (ARM) to uncover frequently occurring conditions and combinations of conditions.

This same statistical technique is used by companies such as Amazon to determine future purchases based on articles people have bought.

Among 81,963 patients with epilepsy, the most common conditions were anxiety and mood disorders (46.5%). These were followed by hypertension (36.9%), back problems (35.2%), developmental disorders (31.6%), and headache including migraine (29.5%). Urinary tract infections (UTIs) were experienced by 22.8% of the sample.

The rate of anxiety and mood disorders was not unexpected, “but I was surprised to see hypertension so high on the list,” said Bensken. He noted there is also increasing evidence pointing to a cardiovascular–epilepsy connection.

What Should Neurologists Do?

The study also highlights the relatively high rate of back problems, which are not usually considered a comorbidity in patients with epilepsy, Bensken said.

“Back problems likely greatly impact a patient’s quality of life, and seeing them so high on the list makes me wonder if neurologists or epileptologists or primary care doctors are even asking about back pain and how that might impact the ability to function day to day,” he added.

How do these rates compare with the general population? From other studies, the estimated prevalence for anxiety and mood disorders is 20%-30%, compared with almost 50% of the current sample, said Bensken.

In addition, the rate of hypertension in the study’s epilepsy population was about 7% higher than the general population, and the rate of UTIs was about 12% higher, he reported.

When examining combinations of conditions, anxiety and mood disorders continued to have an “outsized” prevalence, appearing in nearly every combination, the investigators note.

Almost a quarter (24.7%) of participants had back problems plus anxiety and a mood disorder and about 15% had headaches and back problems as well as anxiety and a mood disorder.

“That’s a non-negligible amount of the population that have not just one or two things going on but three and four,” said Bensken.

These new results underscore how complex these patients can be and the need to integrate medical care among different specialties, he noted.

“We don’t believe it’s the neurologist’s job to also manage the hypertension, but being aware of how prevalent hypertension may be and working with the primary care doctor, or at least checking in with the patient and asking if they’re managing their hypertension, is a real priority,” he said.

Researchers also used the ARM system to identify racial disparities, “which have been largely under-studied in the epilepsy context,” said Bensken.

American Indians and Alaskan Natives had a substantially higher prevalence of developmental disabilities, while Black participants had a higher prevalence of hypertension.

One of the study’s themes was that disparities were not uniform, Bensken noted. “It wasn’t that in every condition the prevalence was lowest for White individuals and highest for everybody else,” he said.

These results point to the need for a larger study to examine the cultural context of these subgroups and such things as structural racism that might drive disparities, he added.

When researchers examined combinations of comorbidities in individuals in the top quartile of hospitalizations and emergency department visits, they found high users had a much higher disease burden, with 75.8% having anxiety or a mood disorder.

The study highlights that patients with epilepsy on Medicaid are “a high priority population,” said Bensken.

Drift Down Hypothesis

Commenting on the findings for Medscape Medical News, Fred A. Lado, MD, PhD, director of epilepsy at Northwell Health Eastern and Central Regions, said the increased incidence of comorbidities in patients of low socioeconomic status was not surprising.

“The interesting data here is that we see an even higher incidence among people with epilepsy,” said Lado, who was not involved with the research.

The study shows how epilepsy exacerbates the effects of low socioeconomic status, he added.

“One of the determinants of socioeconomic status in this case may well be the fact they have seizures and have a limited ability to work and are often more dependent on state assistance and disability support,” Lado said.

He also referred to the “drift down hypothesis” of chronic disease. “If you have epilepsy and are born into a middle-class family, chances are you will be on disability and can’t work, so you probably have a lower socioeconomic status than your family did as you grew up.”

Lado noted how “extremely common” mood disorders are in this population and that certain pain syndromes “tracked with those mood disorders.”

“We know mood disorders are more prevalent in people with epilepsy and now we see that pain-related problems — headache and back pain — are more prevalent in people with epilepsy,” he said.

The data showing “downstream effects of the mood disorders,” from epilepsy to mood disorders to pain disorders, was “very interesting,” Lado said.

The study was funded by the Centers for Disease Control and Prevention and the National Institute on Minority Health and Health Disparities of the National Institutes of Health (NIH). Bensken has reported receiving research support for this work from the NIH.

SOURCE: by Pauline Anderson