Beliefs about medication as predictors of medication adherence in a prospective cohort study among persons with multiple sclerosis

BACKGROUND: Though adherence to disease-modifying therapies (DMTs) among persons with multiple sclerosis (PwMS) varies and is often below 80%, only few prospective studies on adherence examined predictors beyond demographic and clinical characteristics. OBJECTIVES: Identify antecedents to adherence and persistence to DMT in a prospective design among PwMS. METHODS: PwMS (n = 186) were prospectively assessed at three time points: baseline, 6 (Time 1) and 12 months later (Time 2). Clinical, demographic information and patient-reported medication beliefs, illness perceptions, medication habits, perceived health and affect were surveyed in-person. Adherence and persistence were assessed by a combination of self-reports and retrospective review of medication claims. FINDINGS: PwMS were 69.9% (Time 1) and 71% (Time 2) adherent to their DMTs and 64.5.9% were persistent. Beliefs about Medications were consistently predictive at both time points (baseline to Time 1 and Time 1 to Time 2) of medication adherence and persistence whereas other perceptions were predictive in some analyses; clinical and demographic characteristics were mostly not predictive of adherence nor persistence. The prospective association of beliefs about medication with adherence held also in multivariate analyses (OR = 0.88, 95% CI 0.78–0.99, p = 0.029). CONCLUSIONS: Adherence and persistence are predicted by medication beliefs of PwMS. As medication beliefs are modifiable, they should be assessed periodically and targeted as a focus of tailored interventions aimed to improve adherence and consequently health outcomes in PwMS. REGISTRATION: Clinical trials registry #NCT02488343, date: 06/08/2015.