BOSTON (EGMN) –Certain central nervous system-related comorbidities occur significantly more often among people with self-reported epilepsy than in the general population, according to a large survey of U.S. households.
Individuals who reported ever having had epilepsy or a seizure disorder were more likely than those without a self-reported epilepsy diagnosis to have ever had depression, anxiety, bipolar disorder, attention-deficit/hyperactivity disorder, sleep disorder, or migraine a finding that could be an important consideration in the clinical management of epilepsy, Ruth Ottman, Ph.D., reported at the annual meeting of the American Epilepsy Society.
Overall, 2% of 172,959 adults in the National Survey of Epilepsy, Comorbidities and Health Outcomes self-reported an epilepsy diagnosis.
Dr. Ottman, professor of epidemiology and neurology at Columbia University, New York, and her colleagues developed the 11-item screening survey, which was mailed in 2008 to 340,000 households from two national panels selected to be representative of the U.S. population.
The investigators used propensity score-matching to balance the epilepsy and non-epilepsy cohorts with respect to baseline characteristics, risk factors, and panel differences associated with epilepsy, including age, gender, income, population density, geographic region, severe head injury, stroke, and the main effect of panel and interaction terms. To estimate the association of epilepsy with comorbidities, they calculated prevalence ratios using log-binomial generalized linear models, Dr. Ottman said.
Of the 3,488 people who reported having ever had epilepsy or a seizure disorder, 61% were female, the mean age was 48 years, 35% had a seizure or convulsion within the previous 12 months, and 27% reported having had a febrile seizure or convulsion as a child, Dr. Ottman said. Using the propensity matched sample, the investigators determined that 33% of the epilepsy cohort reported ever having depression, compared with 26% of the non-epilepsy controls. Similarly, 22% of the epilepsy cohort vs. 14% of the controls reported a history of anxiety disorder; 14% vs. 7% reported a history of bipolar disorder; and 13% vs. 6% reported having previously been diagnosed with ADHD. Compared with the control group, patients in the epilepsy cohort more frequently reported sleep disorder (20% vs. 14%) or migraine (28% vs. 21%).
Although the survey did not collect information on specific medications, “it is possible that some of the comorbidity in our study could be related to medications,” Dr. Ottman said in an interview. “However, for several of the comorbid disorders we described, other studies have found significantly increased occurrences even before the first seizure, suggesting that medications do not explain all of the comorbidity.” For example, she said, “the prevalence of depression is higher in people with epilepsy than in people without it, even before the first seizure occurs, and this is also true for migraine.”
The precise mechanisms underlying the increased prevalence of certain CNS comorbidities has not been established, but one explanation might be “shared pathogenic mechanism underlying epilepsy and the other disorders, possibly due to shared genetic susceptibilities or to common environmental risk factors,” Dr. Ottman noted.
Clinicians should be aware of the potential for CNS-related comorbidities “so they can be sensitive to patients’ reports of symptoms possibly reflecting other disorders and so they can consider medications that have been found to be effective in treating both epilepsy and some of the comorbid disorders,” Dr. Ottman said. Comorbidities have been highlighted by the National Institute of Neurological Disorders and Stroke as a priority for epilepsy research “and we hope our research will increase awareness of comorbidities even further.”
The study sponsored by Ortho-McNeil Janssen Scientific Affairs, LLC. Dr. Ottman reported no conflicts of interest.
