Abstracts

Rationale: Adverse effects (AEs) of antiepileptic drugs (AEDs) are the most common impediments to optimal drug dosing for complete seizure control. Moreover, they adversely affect health-related quality of life. Better understanding of the clinical properties of AEs is a prerequisite for systematic research of their neurobiological underpinnings, which should support the development of less toxic AEDs. The aims of this study were to define the patterns of AE occurrence in a large sample of patients with epilepsy and to determine their clinical relevance based on their association with subjective health status. Methods: Two hundred consecutive patients with epilepsy completed validated self-report health assessments, including the Adverse Event Profile (AEP) and Quality of Life in Epilepsy Inventory (QOLIE)-89. We performed a factor analysis on the 19 AEP items to identify distinct classes of AEs. A univariate correlation analysis tested for associations between the AE classes and QOLIE-89 scores. In a subgroup of 62 subjects who met criteria for a four-month trial based on AED toxicity, correlations were tested between change in AE classes scores and change in QOLIE-89 scores. Results: AEs were found to segregate into five discrete classes: Cognition and Coordination, Mood and Emotion, Sleep, Metabolism, and Tegument and Mucosa. Figure 1 illustrates the degree of statistical association of each AE within each class, and the unequivocal separation of each class from the others. Each class scores correlated inversely with QOLIE-89 scores (Figure 2). Change in three of five AE classes scores (Cognition and Coordination, Mood and Emotion, and Tegument and Mucosa) correlated positively with change in QOLIE-89 scores. Conclusions: Adverse AED effects detected by a reliable and validated instrument can be classified in five biologically plausible factors. Improvement in specific classes of medication-related toxicity can lead to better subjective health status.