Predicting ongoing adherence to disease modifying therapies in multiple sclerosis: utility of the health beliefs model

OBJECTIVE: To evaluate ongoing adherence to disease modifying therapies (DMT) among individuals with multiple sclerosis and test the utility of the Health Beliefs Model (HBM) to predict adherence. DESIGN: Telephone survey completed at baseline with monthly telephone follow-up for 6 months. SETTING: Veterans Health Administration. PARTICIPANTS: Eighty-nine veterans with MS actively enrolled in a regional VA MS outpatient clinic currently prescribed DMT. MEASURES: Demographic information. Selected items from the Adherence Determinants Questionnaire (ADQ) and Barriers to Care Scale (BACS). RESULTS: Adherence in this population of ongoing DMT users was relatively high (over 80% achieved 80% adherence at follow-up time points). Logistic regression and hierarchical multiple regression analyses controlling for demographics and disease duration were employed to examine the relationship of HBM constructs of perceived susceptibility, severity, benefits, and barriers to DMT adherence and satisfaction at 2-, 4- and 6-month follow-up. Of the four HBM constructs, only perceived benefits uniquely predicted both outcomes across multiple time points. CONCLUSION: Sustained adherence to DMT remains a challenge for an important minority of individuals with MS. The Health Beliefs Model provides insight into psychosocial mechanisms that maintain adherence behavior. In particular, focus upon the perceived benefits of ongoing DMT therapy may be a promising focus for future interventions.