Background: Treatment adherence is fundamental in multiple sclerosis (MS) management. Adherence rates vary significantly between studies and range from only 30% to almost 90%, depending on assessment method and medication type. This study aimed to identify patient-related categories associated with a treatment modification or discontinuation in PwMS with first- and second-line treatment.
Methods: Semi-structured interviews were performed in n = 11 PwMS with first-line treatment and n = 12 PwMS with second-line treatment. Medication history, experiences with prior medication, decision-making processes regarding immunotherapy, adherence behaviour and reasons for adherence/non-adherence were asked for in open 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. A Cohen's kappa of .76 for the PwMS with first-line treatment and .64 for the second-line sample was achieved between the two coders.
Results: One key reason for non-adherence reported by PwMS with first-line treatment was “burdensome side effects,” and for adherence the “belief in medication effectiveness.” In PwMS with second-line treatment, a “lack of perceived medication effectiveness” was a a key category related to changes or a discontinuation of immunotherapy. Reasons for adherence were “positive illness beliefs/perceptions” and “the belief in a highly active disease.” Intentional non-adherence appeared as a major issue for first-line treatment and less relevant for second-line treatment,
Conclusions: This study indicates specific differences in factors mitigating adherence between PwMS with first- and second-line treatment.