The Structural Model of Treatment Adherence Based on Illness Perception with the Mediating Role of Self-Management in Patients with Diabetes

Abstract

This study aimed to test a structural model of treatment adherence based on illness perception, with self-management as a mediating variable, among patients with diabetes in Isfahan, Iran. This applied quantitative study employed a descriptive-correlational design using structural equation modeling. The study population consisted of patients with diabetes, predominantly type 2 diabetes, attending Shahid Sha’baninezhad Diabetes Clinic in Isfahan. A final sample of 293 patients was included through convenience sampling. Data were collected using the Brief Illness Perception Questionnaire (B-IPQ), the Summary of Diabetes Self-Care Activities (SDSCA), and the Madanloo Treatment Adherence Questionnaire. Data were analyzed using SPSS and AMOS. Structural equation modeling was applied to examine the hypothesized relationships, and bootstrap analysis was used to test the mediating effect of self-management. Illness perception had a positive and significant direct effect on treatment adherence (β=0.18, t=2.70, p=0.001) and self-management (β=0.23, t=3.14, p=0.001). Self-management also exerted a significant positive direct effect on treatment adherence (β=0.57, t=5.07, p=0.001). The indirect effect of illness perception on treatment adherence through self-management was significant (β=0.13, p=0.01; confidence interval=0.07–0.27), confirming the mediating role of self-management. The model explained 41% of the variance in treatment adherence and 6% of the variance in self-management. Model-fit indices indicated an acceptable fit to the data (GFI=0.93, AGFI=0.85, CFI=0.96, NFI=0.94, IFI=0.91, χ²/df=2.88, PCFI=0.70, and RMSEA=0.06). Illness perception was associated with treatment adherence both directly and indirectly through self-management, highlighting self-management as an important mediating mechanism in patients with diabetes. Interventions that simultaneously promote accurate and adaptive illness perceptions and strengthen diabetes self-management behaviors may therefore contribute to improved treatment adherence and provide a useful framework for educational and psychological components of comprehensive diabetes care.