SEATTLE ― More than a quarter of patients with epilepsy are prescribed opioids, which is significantly more than in the general population, results of a new study show.
The research also shows that a multitude of pain conditions are more prevalent in epilepsy patients than in patients without epilepsy.
Dr Andrew Wilner
"That raises the question of why," said Andrew Wilner, MD, an epileptologist at Angels Neurological Centers, Abington, Massachusetts, in an interview with Medscape Medical News. "Epilepsy patients have more headaches and fractures, but why would they have more fibromyalgia? Why would they have more jaw pain, and why more chest pain?"
The findings were presented here during the American Epilepsy Society (AES) 68th Annual Meeting.
Most Frequently Prescribed
The new study was inspired by an earlier study by Dr Wilner and his colleagues at Accordant Health Services, Greensboro, North Carolina, that found that after anticonvulsants, opioid analgesics was the most frequently prescribed drug class among insured epilepsy patients.
That study ( Epilepsy & Behavior 2014;41:83-90) was a retrospective analysis of 2012 insurance claims from more than 8000 people with epilepsy in eight US health insurance plans. It also showed that epilepsy patients use healthcare resources primarily for the treatment of seizures, pain, and infections, and that more than half (58%) have at least one comorbidity.
Commenting on that study for Medscape Medical News, Charles E. Begley, PhD, Division of Management, Policy, and Community Health, University of Texas–Houston School of Public Health, in Texas, said that the data come from "good insurance databases" and that the researchers used "standard techniques" to compare costs incurred by people with and without epilepsy.
"I think it's overall a good study," with the cost estimates being "in the ballpark range of what's out there," said Dr Begley. "Most of the things that cause the excess costs in epilepsy are hospitalizations, emergency room visits, and expensive medications."
Dr Wilner's group was surprised to find that 27% of the epilepsy population in that study were prescribed analgesic-opioids. "We were inspired to look at this further because epilepsy is not a painful condition," said Dr Wilner. "Epilepsy doesn't hurt; it's not like rheumatoid arthritis."
Although people with epilepsy suffer more bone fractures than the general population, probably because of falling during a seizure, and they have more migraines, "that doesn't seem to explain" the high use of opioids uncovered by the study, added Dr Wilner.
Larger Group
To further investigate this, the researchers used a larger group of epilepsy patients (10,271) and a control group of 20,542 patients from the managed insurance databases who were matched for age, sex, and insurance type. Control patients were excluded if they had any of a long list of disorders, so they were clinically similar to the epilepsy patients except that they did not have epilepsy.
The analysis showed that 26% of individuals in this expanded epilepsy group used analgesic opioids compared with 18% of control patients (P < .001). As well, the prevalence of each of 16 pain conditions was higher in the epilepsy group than in control group (all P < .05).
For example, 16% of the epilepsy patients and 11% of the control patients had joint pain or stiffness, and 14% of the epilepsy group and 9% of the control group had abdominal pain.
"Every single one of those 16 pain-causing diagnoses was higher, statistically significantly higher, in the epilepsy group," commented Dr Wilner. He added that it was not just a matter of patients complaining on a questionnaire; rather, these were diagnoses that were documented, billed for, and presumably paid for.
Higher usage was true for both men and women. Among women, 30% of those with epilepsy used analgesic opioids vs 20% of control patients (P < .0001). And for men, the percentage using an analgesic opioid was 20% for those with epilepsy and 16% for control patients (P < .0001).
For all groups, the top 80% of analgesic opioid claims were for five products: hydrocodone/acetaminophen (38% of claims), oxycodone/acetaminophen (13%), oxycodone HCL (16%), tramadol HCL (8%), and fentanyl (4%) (all agents are available in multiple brands).
The results beg the question of whether epilepsy patients are somehow more sensitive to pain or are more likely to have their complaints heard because they see their doctor more often than patients who do not have epilepsy.
The "very robust" size of the population strengthens the study findings, commented Dr Wilner. "In these types of studies, there are always caveats, for example, coding issues, but if the numbers are big enough, they ought to be reproducible and a real finding."
Although he said he is not qualified to determine whether the higher use of opioids among epilepsy patients is "appropriate or inappropriate," Dr Begley said he does not find the figures surprising and that the difference could probably be explained by excess injuries in epilepsy patients.
Frequent Physician Visits?
But for Michael Privitera, MD, professor of neurology and director of the Epilepsy Center, University of Cincinnati Neuroscience Institute, in Ohio, a higher rate of opioid use among epilepsy patients "doesn't ring true" for his practice.
"It's certainly not the case in terms of my prescriptions, or prescriptions out of our practice," he said, adding that his epilepsy clinic has seven specialists and treats between 2000 and 3000 patients.
Dr Privitera said that he can think of only one or two epilepsy patients in his practice who have fibromyalgia, "which doesn't seem to be out of proportion to the incidence in general." The study found that fibromyalgia affected 4% of the epilepsy group vs 3% of the control group.
He agreed that more frequent physician visits may help explain any differences. "Maybe people with epilepsy, because they're younger and have a chronic illness, go to a physician more frequently and therefore may be tied into the healthcare system more."
Dr Privitera also commented that side effects of anticonvulsant drugs may contribute to the prevalence of pain conditions.
Dr Wilner is a medical advisor for Accordant Health Services, a wholly owned subsidiary of CVS Health. He is also an editorial advisor to Medscape Medical News.
American Epilepsy Society (AES) 68th Annual Meeting. Poster 1.270. Presented December 6, 2014.
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Cite this: Pain Conditions, Meds Prevalent in Epilepsy Patients - Medscape - Dec 07, 2014.
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