Treatment adherence and other patient-reported outcomes as cost determinants in multiple sclerosis: a review of the literature

Background: Treatment adherence is one of the key factors for achieving optimal clinical outcomes. In order to assess costs related to adherence to, and persistence and compliance with, disease-modifying therapies (DMTs) in patients with multiple sclerosis (MS), a narrative review of the literature was performed. Satisfaction with and preference for DMTs and their delivery devices were also assessed, as both can have an influence on patients' adherence and persistence. Methods: Electronic databases (MEDLINE, PubMed, Google Scholar, congress proceedings) were searched to identify publications analyzing MS costs related to adherence, persistence, satisfaction, and preferences for MS treatments. Bibliographic references were hand searched. English or Spanish studies published between January 2007 and January 2013 were selected. Results: A total of 398 titles were identified, of which 12 met the inclusion criteria. Six studies evaluated the impact of adherence, persistence, and compliance on treatment costs; four publications analyzed satisfaction with DMTs; and two assessed treatment preferences based on attributes of the delivery device. Increased adherence and persistence were associated with better clinical outcomes, leading to lower relapse risk (odds ratio [OR]: 0.71; 95% confidence interval [CI]: 0.59-0.85) and a decrease in health care resource use, such as MS-related hospitalizations (OR: 0.63; 95% CI: 0.47-0.83) and emergency department visits (OR: 0.80; 95% CI: 0.60-1.07). This reduction in resource use led to a patient/year total cost reduction (excluding DMT costs) of up to 22%. Conclusion: This review highlights the importance of ensuring adequate adherence in MS patients through treatments and devices better tailored to patients' needs that could enhance clinical outcomes and reduce MS costs. Understanding the factors underlying satisfaction and compliance with treatment and patients' preference for certain therapies could help in the development of strategies that can improve adherence.