Abstract
OBJECTIVE: This study aims to investigate the mediating role of health literacy-both in hypertensive patients and their spouses -on the relationship between illness perception and medication adherence, based on the Actor-Partner Interdependence Mediation Model (APIMeM). METHODS: Hypertensive patients and their spouses from a selected region were recruited through convenience sampling between August 2024 and March 2025. Data were collected using the General Information Questionnaire, Brief Illness Perception Questionnaire, Health Literacy Scale for Chronic Disease Patients, Morisky Medication Adherence Scale, and the Caregiver Self-care Contribution Scale. RESULTS: (1) Regarding the actor effects, patients' health literacy partially mediated the relationship between their illness perception and medication adherence (effect size: 0.028, 95% CI: 0.007~0.067, P < 0.05). Similarly, spouses' health literacy partially mediated the effect of their own illness perception on their medication adherence (effect size: 0.240, 95% CI: 0.165~0.324, P < 0.05). (2) For the partner effects, patients' health literacy partially mediated the relationship between their spouse's illness perception and the patient's medication adherence (effect size: 0.042, 95% CI: 0.018~0.084, P < 0.05). Meanwhile, the spouse's health literacy fully mediated the effect of the patient's illness perception on the spouse's medication adherence (effect size: 0.139, 95% CI: 0.020~0.302, P < 0.05). CONCLUSION: A bidirectional actor-partner effect exists between illness perception and medication adherence among hypertensive patients and their spouses. Health literacy plays a significant mediating role in these relationships. These findings suggest that clinical interventions should target both patients and their spouses simultaneously, enhancing health literacy, strengthening disease knowledge, improving illness perception, and thereby promoting better medication adherence.