Assessing Barriers to Adherence with the Use of Dimethyl Fumarate in Multiple Sclerosis.

Background: Multiple sclerosis (MS) is a chronic, inflammatory, central nervous system demyelinating disease that requires long-term use of disease-modifying therapies (DMT). Patient adherence to DMT is key in reducing the inflammation that leads to relapses and neurodegeneration. Dimethyl fumarate (DMF) poses unique challenges to adherence including being the only twice-daily dosing DMT. Previous research suggests there are direct roles that providers play on improving their patients' adherence rates, such as focusing on the patient-provider relationship, helping put the patient at ease so that they feel understood and respected. Also, route of administration affects adherence in other chronic healthcare conditions. However, the issue of adherence to DMT in MS is more complex than just route of administration, with adverse effects being the main predictor of adherence.

Objectives: (1) To define various patient specific factors (e.g. fatigue and mood disorders) that affect adherence with DMF and (2) to understand how patients' perceptions of treatment satisfaction (such as effectiveness, convenience, side effects and global satisfaction) and DMFs impact on quality of life (such as social support, activities of daily living, coping) influence adherence.

Methods: Our study was a prospective, observational measurement of adherence to treatment with DMF in MS patients over 52 weeks. Twenty-five out of thirty-five patients enrolled completed the study. Adverse event (AE) data was reviewed on all participants.

Results: Adherence rates correlated with patient's perceived effectiveness (0.25, p < 0.023) and the level of bothersome symptoms the patient experienced (0.45, p < 0.0001). The majority of new AE onset was reported within 12 weeks of DMF initiation. This is consistent with previously published data with DMF use.

Conclusion: Adherence rates are an important factor to be considered when starting patients on DMT. DMF creates its own barriers to adherence with our study highlighting some, including twice-daily dosing and AEs experienced following treatment initiation. Healthcare providers should be aware of these barriers prior to treatment initiation and counsel patients appropriately.