BACKGROUND: There is a lack of a standardized tool for adherence measurement in patients with epilepsy. Studies in children with epilepsy have reported adherence in 50-96.5%. The primary objective of this study was to identify predictors of nonadherence to antiepileptic drugs (AEDs) using two different methods in Jordanian children and adolescents with epilepsy.
METHODS: Participants included 63 children and adolescents with epilepsy and their primary caregivers. Adherence measures included a subjective approach (using parent and child self-reports via Medication Adherence Report Scale (MARS)) and an objective method (measuring plasma levels of AEDs coupled with the application of population pharmacokinetic models to predict AED concentrations in the children). The Beliefs about Medicines Questionnaire (BMQ) was used to examine the association beliefs about medicines with nonadherence in the participating patients.
RESULTS: Measuring AEDs in plasma samples captured the highest percentage of nonadherence (36.2%). No significant agreement was found between the AED plasma level method and both the MARS (parent) and MARS (child). The overall nonadherence (combined methods) to AED therapy in children with epilepsy was 44.4%. Logistic regression analysis indicated that children with longer duration of disease were more likely (odds ratio [OR]: 1.54, 95% confidence interval [CI]: 1.16-2.04) to be classified as nonadherent as were children whose parents have lower AED Necessity scores (OR: 0.68, 95% CI: 0.53-0.87) and higher AED Concerns (OR: 1.6, 95% CI: 1.26-2.04) as measured by the BMQ.
CONCLUSION: The use of a multimethod approach for assessing adherence increases sensitivity for detection of nonadherence to antiepileptic drugs. Disease duration and parental necessity, beliefs, and concerns assessed by the Beliefs about Medicines Questionnaire-specific questionnaire were significant predictors of nonadherence to the antiepileptic drug therapy. The need for the development and implementation of interventions that can be employed to improve adherence within this pediatric population has been highlighted by the high levels of nonadherence identified.