Abstract
OBJECTIVE: Poor medication adherence is common among breast cancer patients undergoing endocrine therapy. Although previous studies have shown that symptom distress, illness perception, and fear of recurrence can have a connection with medication adherence, the underlying mechanism remains unclear. This study explored the effect of symptom distress on medication adherence, the mediating role of illness perception between symptom distress and medication adherence, and the moderating role of fear of recurrence among those factors. METHODS: Symptom distress, illness perception, fear of recurrence, and medication adherence were assessed in 405 patients. A structural equation model verified the mediating role of illness perception, and a multi-cluster analysis tested the moderating role of fear of recurrence. RESULTS: Illness perception had a mediating effect between symptom distress and medication adherence (effect size: -0.213), accounting for 28% of the total effect. A significant difference was observed in the path coefficient of "illness perception → medication adherence" between the low and high fear of recurrence group (CR = |-3.578| > 1.96, P < 0.05). In the high fear of recurrence group, the association between symptom distress and medication adherence was mediated by illness perception, while in the low fear of recurrence group, medication adherence was only connected by symptom distress. CONCLUSIONS: The links of symptom distress and medication adherence were mediated by illness perception, whereas fear of recurrence moderated this relationship. To improve medication adherence, oncology nurses should alleviate symptom distress and implement interventions for patients with high fear of recurrence to reduce negative illness perception.