Medication habits among persons with multiple sclerosis.

Background: Though habitual behavior is part of medication-taking behavior, studies of adherence to medication among persons with relapsing remitting multiple sclerosis (PwRRMS) have not prospectively examined habit in relation to disease-modifying treatments (DMTs).

Objectives: 1. Examine habit dimensions - repetition, lack of awareness, and lack of control - across time and route of administration (oral vs. injectable). 2. Examine the association (prospective and cross sectional) of the dimension of repetition and the habit index with adherence and persistence in medication taking and to medication perceptions.

Methods: PwMS (n = 140), in their first year of treatment with a DMT, were prospectively assessed at three time points: at baseline, 6 months later (Time 1), and 12 months later (Time 2). Clinical and demographic information were obtained in-person, as were patient-reported medication habits and medication perceptions. Adherence and persistence were assessed with a combination of self-reporting and retrospective review of medication claims.

Results: Repeated measures analysis of variance (ANOVA), with dimension as the within-subject factor at each time point, indicated that the repetition dimensions at all points were significantly higher than lack of awareness and lack of control dimensions. Repeated measures ANOVA, with time as the within-subject factor and route of administration as between-subject factor, yielded a significant time effect in repetition and lack of awareness dimensions so that they increased across time but not in lack of control; administration route effects were found to be nonsignificant in all dimensions. Repetition at Time 1 was positively associated with patient-reported adherence at this time point (r = 0.33, p = 0.002) but this was not consistently found at other time points . Likewise, reported repetition at Time 1 was higher among PwRMS who persisted with their medication a year later than among those who did not persist. Perceptions of medication (concern, harm, and overtreatment) were significantly negatively associated with reported repetition.

Conclusions: Over time, PwRMS reported an increase in two habit dimensions, repetition and lack of awareness, in medication taking. No significant differences in habit by administration modality were found. The habit dimension of repetition was significantly associated with perceptions of medication, adherence, and prospectively predicted persistence. However, the low values obtained for lack of awareness and lack of control, compared with the higher levels of repetition, indicate that the habit is not well ingrained. Hence, intervention to target habit formation and maintenance, to be tailored to the individual, are a promising venue for enhancing medication adherence and improving disease outcomes.