ABSTRACT
BACKGROUND: Self-efficacy, a patient-level factor, has been shown to facilitate patient engagement in treatment and optimize treatment-related outcomes in various health contexts. Research on interventions supporting hepatitis C virus (HCV) direct-acting antiviral (DAA) treatment uptake and adherence among persons who inject drugs (PWID) is needed, but whether self-efficacy factors influence DAA treatment cascade outcomes in this population has been less studied. METHODS: Using the HERO study data, we analyzed a subset of participants with any general health self-efficacy data (n=708) measured at baseline and end-of-treatment time points using a 5-items instrument (facets: 'goal setting', 'goal attainment', 'having a positive effect', 'being in control', and 'working to improve'). The cascade outcomes included DAA treatment initiation, duration, adherence, completion, and sustained virologic response (SVR). The effect of baseline and change (Δ) scores for composite and item-level self-efficacy on the cascade outcomes was assessed using logistic regression and generalized linear models. RESULTS: Higher baseline composite self-efficacy [adjusted odds ratio (95 % confidence interval) =1.57 (1.07, 2.29)], 'goal attainment' [1.31 (1.03, 1.67)] and 'having a positive effect' [1.33 (1.03, 1.74)] were associated with greater likelihood of treatment initiation. 'Δ Goal attainment' was significantly associated with SVR [1.63 (1.04, 2.53)]. 'Δ Being in control' and 'Δ working to improve' were associated with treatment adherence and duration, respectively. CONCLUSIONS: General health self-efficacy positively influences DAA treatment initiation among PWID. 'Goal attainment' facilitates the achievement of DAA treatment-related outcomes. Further studies should assess the effect of self-efficacy related to performing healthcare tasks specific to DAAs on the treatment-related outcomes.
