SEATTLE – Epileptic children are less likely to take antiepileptic drugs as prescribed if they also have psychiatric illnesses, according to a review of an administrative claims database.
“It's well established that nonadherence to prescribed antiepileptic drugs has serious potential consequences, including exacerbation of seizures, morbidity, and, now we are learning, even potentially mortality,” said Dr. Alan B. Ettinger, a neurologist at the Comprehensive Epilepsy Center at North Shore Long Island Jewish Medical Center, New Hyde Park, N.Y. “Establishing a possible relationship between these issues–psychiatric comorbidity and adherence–really has practical utility because if this is the case, then clinicians need to use some special interventions to try to promote better adherence.”
Using a PharMetrics administrative claims database, Dr. Ettinger and his colleagues reviewed claims for January 2000 through December 2006 for more than 50 million individuals covered by U.S. managed care plans.
The researchers found 5,343 children aged 4-18 years who had a diagnosis of epilepsy, received at least one prescription for an antiepileptic drug (AED), and were enrolled in their health plan for at least 1 year before and 1 year after starting the medication. There were slightly more boys than girls (55%), and about half of the children were 11 years old or younger.
Fully 65% of the children were nonadherent to their AED therapy. The children's mean medication possession ratio, a measure of adherence, was 0.54. Children with a ratio of less than 0.8 were considered nonadherent. The ratio was calculated by dividing the total number of days for which AEDs were supplied during the 1-year follow-up period by 365 days, Dr. Ettinger said at the annual meeting of the American Epilepsy Society.
Nearly half of the children had a psychiatric illness, as diagnosed by any physician, said Dr. Ettinger.
The most common were attention-deficit/hyperactivity disorder (17%) and attention deficit disorder (10%). But sizable proportions of children had more serious psychiatric illnesses, such as bipolar disorder (8%), developmental disorders (5%), schizophrenia (1%), or other psychoses (7%).
In multivariate analyses that took into account age, sex, geographic region, overall comorbidity burden, type of AED (newer vs. older), starting regimen (monotherapy vs. combination therapy), and initial AED dosing (one or fewer pills daily vs. more), children were significantly more likely to be nonadherent if they had a diagnosis of attention-deficit/hyperactivity disorder or bipolar disorder before starting AED therapy (odds ratios, 1.17 and 1.22, respectively) and if they received a diagnosis of bipolar disorder after starting AED therapy (odds ratio, 1.37).
Schizophrenia alone was not associated with elevated odds of nonadherence. But relative to their counterparts who did not have any of the more serious psychiatric illnesses, children who had at least one of them (regardless of type) were significantly more likely to be nonadherent (odds ratio, 1.15).
“Recognizing psychiatric comorbidity in pediatric patients with epilepsy is very important, and we hope that this study lends another compelling reason why clinicians need to be screening for psychiatric comorbidity,” concluded Dr. Ettinger, who reported that he is a project consultant for GlaxoSmithKline.