Determinants of Anti-Seizure Medication Non-adherence and Response to Treatment Among People with Epilepsy in Kilifi, Kenya

Abstract

The epilepsy treatment gap (ETG) and poor adherence to antiseizure medications (ASMs) remain major challenges in low- and middle-income countries (LMICs). This study assessed adherence, evaluated the effectiveness of short messaging service (SMS) reminders, and investigated ASM-related adverse drug reactions (ADRs) in epilepsy patients from Kilifi and Nairobi, Kenya. A cohort of 1,692 people with epilepsy was assessed for medication adherence, with 38% having drug level data. In Kilifi, a randomised controlled trial (RCT) involving 1,038 participants tested SMS interventions (text, audio, both) versus control. Drug levels were measured at baseline, three, six and twelve months and a third of these were available at the time of analysis. At baseline, adherence was low—overall gap was 68% (71% in Nairobi, 65% in Kilifi). Factors associated with poor adherence included active epilepsy (aOR=1.80), ASM polytherapy (aOR=3.1), and low quality of life (β=-0.007). The SMS intervention in Kilifi reduced non-adherence over time. ASM levels below the quantification limit decreased from 34% at baseline to 29% at follow-up. Suboptimal levels dropped from 64% to 57%. However, overall incidence rate of non-adherence showed no significant difference across intervention groups. Proportion of secondary outcomes improved: daily seizures fell from 22% to 3%, severe disability from 33% to 16%, and negative beliefs from 29% to 20%. SMS reminders reduced the incidence rate of poor quality of life in those with adequate ASM levels but increased incidence rate of severe disability in those with low/suboptimal levels. ADRs affected 68% of 138 participants with mainly psychiatric (59%) and movement symptoms (51%) reported. Risk factors associated with ADR included polytherapy (aOR=2.3) and phenobarbital use. Psychiatric comorbidities were associated with polytherapy use, including depression (aOR=2.9) and psychosis (aOR=1.9). Electrolyte imbalances were found in 19.4% of 1,495 participants, notably hypomagnesaemia (associated with CBZ use) and hyponatraemia (associated with polytherapy use). Addressing side effects, monitoring ASM levels, and implementing comprehensive interventions are essential to reduce the ETG and improve adherence in LMICs