SEATTLE—ADHD or a serious mental illness may lead to the suboptimal adherence to antiepileptic drugs (AEDs) among pediatric patients who have epilepsy, reported researchers at the 62nd Annual Meeting of the American Epilepsy Society.
Alan B. Ettinger, MD, and colleagues analyzed the retrospective claims of pediatric managed care enrollees included in the PharMetrics database from 2000 through 2006. All participants were ages 4 to 18, had been diagnosed with epilepsy or nonfebrile convulsion, had received at least one AED prescription, and had continuous health plan enrollment for one year or longer both prior to and following AED initiation.
Measuring AED Adherence Among Pediatric Patients
Adherence was measured using the medication possession ratio (MPR), defined as the sum of AED days supplied during the year following initiation divided by the number of days in the follow-up period. “This really looks at the total patient supply of AEDs as the measure of prescription refills versus the total amount of time that the patient should be on the antiepileptic drug,” explained Dr. Ettinger, Chief of the Division of Epilepsy and Electroencephalography and Vice Chairman of Neurology at Long Island Jewish Medical Center in New Hyde Park, New York. Nonadherence was defined as an MPR of 0.8 or less.
“Establishing a potential relationship between these issues—psychiatric comorbidity and adherence—has practical utility, because it offers the opportunity to identify individuals who are at particularly higher risk for nonadherence and its complications,” said Dr. Ettinger.
High Incidence of Nonadherence in Children
The mean MPR among 5,343 children (55% male; 48% ages 4 to 11) was 0.542. A total of 65% of participants were nonadherent. Comparatively, 41% of elderly patients were nonadherent in a recent study using the same criteria, noted Dr. Ettinger.
Ten percent of subjects had ADD, and 11% had ADHD. At least one serious mental illness was seen in 23%, of whom 44% had bipolar disorder. A history of ADHD increased the likelihood of nonadherence by 17% (odds ratio [OR], 1.167). A history of bipolar disorder was associated with a 22% increased likelihood of nonadherence.
No other serious mental illness had a significant impact on adherence. However, presence of at least one serious mental illness increased the likelihood of AED nonadherence by 15% (OR, 1.148). “Having more than one psychiatric diagnosis, irrespective of the diagnosis, also was associated with an increased risk in nonadherence,” Dr. Ettinger indicated.
“We hope that this study adds another compelling reason why doctors need to be screening for psychiatric comorbidity,” Dr. Ettinger concluded.
—Marguerite Spellman