Self-reported and measured adherence to hepatitis C direct-acting antiviral therapy and sustained virologic response among people who inject drugs: The HERO study.

Background: Objective adherence measures, such as electronic blister pack (BP), for direct-acting antivirals (DAAs) for hepatitis C virus (HCV) treatment have high accuracy, but their use is limited in real practice settings. We examined the association of self-reported adherence using a visual analogue scale (VAS) with objective BP adherence and sustained virologic response (SVR) among people who inject drugs.
Methods: We conducted secondary analyses using a subset of participants (N = 493) from the per-protocol sample of the HERO study, a pragmatic randomized trial of HCV treatment interventions that used both VAS and BP to measure adherence to a 12-week sofosbuvir/velpatasvir DAA regimen. Multivariable mixed-effects regression models tested the association of self-report adherence level with longitudinal weekly objective adherence. Multivariable logistic regression tested the association of self-report adherence with SVR.
Results: The average VAS and BP adherences were 95.1 % (SD = 8.9 %) and 76.0 % (16.0 %), respectively, and the proportion of the participants achieving SVR was 92.9 %. The estimated adjusted mean objective adherence was significantly different (-16 %; 95 % CI: -22 %, -11 %, p < .001) between participants with 100 % and <80 % VAS adherence. The likelihood of SVR was significantly lower for those with <80 % VAS adherence [adjusted OR = 0.07; 95 % CI: 0.02, 0.24; p < .001] compared to those with 100 %.
Conclusion: Self-reported adherence overestimated objective adherence. However, higher self-report adherence was significantly associated with higher objective adherence. Also, self-reported adherence ≥80 % was significantly associated with SVR. Thus, the self-report measure has utility as a monitoring tool for adherence during DAA treatment.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023. Published by Elsevier B.V.)