Leading representatives of the American Epilepsy Society, American Academy of Neurology, and the Epilepsy Foundation today reported they have grave concerns about the implications and potential misuse of the anticonvulsant (AED) drug comparisons study recently released by the U.S. Agency for Health Research and Quality (AHRQ). The study's intent is to provide an evidence-based analysis of the Effectiveness and Safety of Antiepileptic Medications in Patients With Epilepsy. But the AHRQ report has little clinical value according to the specialists in neurology and epilepsy and could negatively impact patient care.
The AHRQ report is an examination of the comparative efficacy, safety, and tolerability of newer versus older and innovator versus generic antiepileptic medications. The representatives and their organizations strongly support evidence-based medicine and comparative effectiveness research, which they believe improves quality of care. At issue, however, is the study focus, which fails to recognize the different types of epilepsy and deals with this multiform disorder as if it were a monolithic and homogeneous condition. The study further compares effectiveness of old-line anticonvulsants to newer epilepsy drugs irrespective of epilepsy type. Given that seizures have vastly different pathologies and the use of AEDs differs greatly based on the underlying pathology, the old versus new comparison is irrelevant to clinical practice.
"The major problem is the shoehorning of all new drugs and most old drugs into two groups," notes Edward Faught, M.D., of Emory University, and who chairs the American Epilepsy Society's Treatments Committee. "The study author's assertion that differences between the groups are not too marked to allow pooling defies biological credibility and may lead to dangerous decisions based on economic factors alone."
The AHRQ report concludes there are, "No significant differences in the risk of maintaining seizure freedom" when newer antiepileptic medications were compared versus carbamazepine (CBZ), phenytoin (PHT), and valproate (VPA).
"It is possible to read the conclusions simplistically and to determine that there is little justification for not using carbamazepine or valproate first," Faught says. He notes also that the study's equivalent efficacy results between old and new drugs depend heavily upon the inclusion of two drugs in the analysis that are less effective for new-onset seizures, gabapentin and vigabatrin. The first is known to be relatively inefficacious for these seizures, while the latter is a rarely used special-purpose anticonvulsant.