Illness Perception, Self-Efficacy, and Medication Adherence in Patients With Coronary Artery Disease: A Path Analysis of Conceptual Model

Introduction: Illness perception and self-efficacy in patients with coronary artery disease (CAD) may affect medication adherence, which is one of the most important challenges in disease management in this group of patients. Objective: The present study aimed to investigate the factors influencing medication adherence in CAD patients, especially the effect of illness perception and self-efficacy. Methods: This study was cross-sectional and conducted from April to September 2021. A total of 259 patients with confirmed CAD were selected by convenience sampling method based on inclusion criteria. Illness perception, self-efficacy, and medication adherence were investigated using Brief IPQ, SCSES, and MARS_10 questionnaires, respectively. The data were analyzed using the STATA software (version 14) and the regression path analysis method. Results: Patients had moderate illness perception and high self-efficacy, and 61.8 of them adhered to their medication regimen. Greater illness perception, better self-efficacy, and higher education had a positive effect on medication adherence, and increasing age had a negative effect on it. The final path model shows a good fit of the data in the model (χ2: 0.37, df: 274, χ2/df: 0.36, CFI: 1, IFI: 0.95, TLI: 1.07, and RMSEA: 0.00). Conclusion: The results of the present study suggest that patients' illness perception can play an important role in predicting self-efficacy in disease management and the level of medication adherence in patients with CAD. To improve self-efficacy and medication adherence, future intervention studies should focus on the patient's illness perceptions and their improvement.