Applying a perceptions and practicalities approach to understanding nonadherence to antiepileptic drugs

Objective: Nonadherence to antiepileptic drugs (AEDs) is a common cause of poor seizure control. This study examines whether reported adherence to AEDs is related to variables identified in the National Institute for Health and Clinical Excellence (NICE) Medicines Adherence Guidelines as being important to adherence: perceptual factors (AED necessity beliefs and concerns), practical factors (limitations in capability and resources), and perceptions of involvement in treatment decisions.

Methods: This was a cross-sectional study of people with epilepsy receiving AEDs. Participants completed an online survey hosted by the Epilepsy Society (n = 1,010), or as an audit during inpatient admission (n = 118). Validated questionnaires, adapted for epilepsy, assessed reported adherence to AEDs (Medication Adherence Report Scale [MARS]), perceptions of AEDs (Beliefs about Medicines Questionnaire [BMQ]), and patient perceptions of involvement in treatment decisions (Treatment Empowerment Scale [TES]).

Results: Low adherence was related to AED beliefs (doubts about necessity: t(577) = 3.90, p < 0.001; and concerns: t(995) = 3.45, p = 0.001), reported limitations in capability and resources (t(589) = 7.78, p < 0.001), and to perceptions of a lack of involvement in treatment decisions (t(623) = 4.48, p < 0.001). In multiple logistic regression analyses, these factors significantly (p < 0.001) increased variance in reported adherence, above that which could be explained by age and clinical variables (seizure frequency, type, epilepsy duration, number of AEDs prescribed).

Significance: Variables identified in the NICE Medicines Adherence Guidelines as potentially important factors for adherence were found to be related to adherence to AEDs. These factors are potentially modifiable. Interventions to support optimal adherence to AEDs should be tailored to address doubts about AED necessity and concerns about harm, and to overcome practical difficulties, while engaging patients in treatment decisions.