Self-efficacy Mediates Perceived Benefits and Barriers of Adherence of Heroin-dependent Patients to Methadone for Addiction Treatment: A Health Belief Model Study

OBJECTIVE: Although methadone for addiction treatment (MAT) has been widely used in China, the low adherence rate in MAT clinics poses a great challenge. We aimed to investigate the factors related to the adherence of heroin-dependent patients to MAT based on the Health Belief Model (HBM) in Sichuan, China. METHODS: A cross-sectional structured interview was conducted between August and November 2018. Stratified multi-stage sampling was carried out. A total of 581 participants were enrolled from 5 clinics and completed the face-to-face structured interview. Univariate, adjusted logistic regression, multivariate logistic regression analysis and the structural equation modeling (SEM) were employed to explore the association between constructs of HBM and adherence to MAT among heroin-dependent patients. RESULTS: The adherence rate of MAT was 79.3% in the past 6 months. Among all constructs of HBM, self-efficacy (AOR: 1.16, 95% CI: 1.10, 1.22), perceived benefits (AOR: 1.05, 95% CI: 1.00, 1.10) and perceived barriers (AOR: 0.87, 95% CI: 0.77, 0.98) were associated with adherence to MAT. Self-efficacy was directly associated with adherence to MAT (beta = 0.347, P < 0.05). Perceive benefits (beta = 0.276, P < 0.01) and perceived barriers (beta = -0.241, P < 0.05) were directly associated with self-efficacy. However, perceived benefits (beta = 0.096, P < 0.01) and perceived barriers (beta = -0.084, P < 0.01) were only indirectly associated with adherence to MAT. CONCLUSION: The adherence of heroin-dependent patients to MAT can be explained by self-efficacy, perceived benefits and barriers. Self-efficacy plays a significant role as a mediating variable. Future interventions should be considered to improve patients' self-efficacy to MAT.