Social support and medication adherence among adult myasthenia gravis patients in China: the mediating role of mental health and self-efficacy

Background: Myasthenia gravis (MG), a rare chronic neuromuscular disorder, is characterized by progressive physical decline and requires long-term pharmacological treatment. Due to the decline of physical and social abilities, MG patients are in great need of social support, including tangible and emotional support. This study aims to examine the association between social support and medication adherence and the possible mediating effects of mental health and self-efficacy among MG patients. Methods: A cross-sectional analysis of a nationwide MG registry was conducted on 865 patients under oral medication treatment in China between June and July 2022. Validated scales were used to measure the respondent’s mental distress (Four-item Patient Health Questionnaire), social support (Modified Medical Outcomes Study Social Support Scale), self-efficacy for medication use (Self-efficacy for Appropriate Medication Use Scale), and medication adherence (Morisky Medication Adherence Scale, MMAS). Results: The association between social support and medication adherence and possible mediating effects of mental distress and self-efficacy were tested by structural equation model, with significant demographic and disease-related factors adjusted. The respondents showed a very low level of medication adherence (71.2% poor adherence; 1.4% high adherence; mean MMAS = 4.65). The level of social support was positively associated with medication adherence, and such association was fully mediated by two indirect pathways: through self-efficacy (β = 0.07, proportion mediated = 63.8%); and through mental distress and then self-efficacy (β = 0.01, proportion mediated = 6.7%). Conclusion: Provision of social support and interventions on mental health with emphasis on improving self-efficacy for medication use may effectively improve medication adherence among MG patients.