Exploring Adherence to First-Line and Second-Line Immunotherapies in Multiple Sclerosis: An Interview Study

Background: Treatment adherence is fundamental in multiple sclerosis (MS) management. Adherence rates vary significantly between studies, ranging from 30% to almost 90%, depending on assessment method and medication type. This study aimed to identify patient-related categories associated with treatment modification or discontinuation in people with MS receiving either first- or second-line treatment.

Methods: Semistructured interviews were performed with 23 people with MS: 11 receiving first-line treatment and 12 receiving second-line treatment. Medication history, experiences with previous medications, decision-making processes regarding immunotherapy, adherence behavior, and reasons for adherence/nonadherence were explored using open-ended questions. Qualitative content analysis was performed using a combined deductive-inductive approach in building a coding frame. Differences in coding frequencies were compared between the two groups and analyzed quantitatively. Cohen's kappas of 0.76 for people with MS receiving first-line treatment and 0.64 for the second-line sample were achieved between the two coders.

Results: One key reason for nonadherence reported by first-line-treated people with MS was burdensome side effects, and for adherence was belief in medication effectiveness. In people with MS receiving second-line treatment, lack of perceived medication effectiveness was a key category related to changes in or discontinuation of immunotherapy. Reasons for adherence were positive illness beliefs/perceptions and belief in highly active disease. Intentional nonadherence was a major issue for first-line treatment and less relevant for second-line treatment.

Conclusions: These results indicate specific differences in factors mitigating adherence in people with MS receiving first- and second-line treatment.