Factors Associated With Disease-Modifying Therapy Adherence and Persistence in Multiple Sclerosis: A Scoping Literature Review

BACKGROUND: Patients with multiple sclerosis (MS) receiving disease-modifying therapies (DMT) show published adherence rates of 27.0% to 93.8% and published persistence rates of 49.7% to 96.5%. Improvements in DMT adherence and persistence are key to optimizing MS care, and enhanced understanding could improve MS disease management and identify research gaps. This scoping literature review aims to examine the nature and findings of the literature evaluating factors associated with DMT adherence and persistence in patients with MS. METHODS: Eligible articles included in the literature review were quantitative clinical studies written in English, included adherence or persistence as primary outcomes, and accounted for covariates/confounders. The articles were assessed to identify factors associated with adherence/persistence and analyzed according to DMT type (self-injectable, oral, infusion). RESULTS: Fifty-eight studies (103,450 patients) were included. Study distribution by DMT type was self-injectable only (n = 41), oral only (n = 2), infusion only (n = 1), and more than 1 type (n = 14). Older age and previous DMT use were associated with increased adherence and/or persistence. Increased alcohol consumption, DMT adverse events, higher education, and higher body mass index were negatively associated with adherence and/or persistence. Greater number and severity of relapses was associated with increased adherence but decreased persistence. CONCLUSIONS: Most studies examined factors associated with adherence and persistence to self-injectable DMTs. These factors should be evaluated further for oral and infusion DMTs. Insights into the modifiable factors associated with adherence and persistence could guide treatment decisions and help improve adherence and clinical outcomes.