The relationship between illness uncertainty and preoperative anxiety in surgical patients: the moderating role of mental health literacy

Objective: Preoperative anxiety is a common and clinically significant psychological condition among surgical patients, and illness uncertainty is considered an important psychological stressor for preoperative anxiety. Mental health literacy is an intervenable psychological resource, and its role in preoperative anxiety remains underexplored. This study aims to investigate the relationship between illness uncertainty and preoperative anxiety in surgical patients and further examine the moderating role of mental health literacy in this relationship. Methods: A cross-sectional study design was adopted. From August to October 2025, 342 surgical patients were conveniently sampled from a tertiary hospital in central China. The Mishel Illness Uncertainty Scale (MUIS), State-Trait Anxiety Inventory-State subscale (STAI-S), and the Short Version of the Mental Health Literacy Questionnaire for Adults (MHLq-SVa) were used for assessment. Descriptive statistics, univariate analysis, and Pearson correlation analysis were conducted. Multivariate linear regression and moderation analysis were used to test the potential moderating effects of mental health literacy in the relationship between illness uncertainty and preoperative anxiety. Results: for interaction < 0.001). Among patients with lower mental health literacy (Mean-SD), the association between illness uncertainty and preoperative anxiety was stronger, while among those with higher mental health literacy (Mean + SD), this association significantly attenuated. Conclusion: Mental health literacy plays a moderating role in the relationship between illness uncertainty and preoperative anxiety in surgical patients. Higher levels of mental health literacy are associated with a weaker association between illness uncertainty and preoperative anxiety, while lower levels are associated with a stronger association.