Treatment Adherence and Support for People Who Inject Drugs Taking Direct-Acting Antiviral Therapy for Hepatitis C Infection

Phillip Read; Rosie Gilliver; John Kearley; Rebecca Lothian; Evan B. Cunningham; Karen J. Chronister; Gregory J. Dore

Disclosures

J Viral Hepat. 2019;26(11):1301-1310. 

In This Article

Abstract and Introduction

Abstract

A community-based public health facility in Sydney, Australia, the Kirketon Road Centre (KRC), provides health care to people who inject drugs (PWID), homeless and other marginalized people. Since March 2016, KRC has provided treatment for chronic hepatitis C virus (HCV) with direct-acting antivirals (DAAs). We aimed to evaluate treatment adherence amongst clients taking DAAs in a highly marginalized population. All clients who commenced DAA therapy prior to March 2018 at KRC were included in this observational cohort with a subset of clients attending daily or weekly for enhanced adherence support and dosing. Demographic, behavioural, clinical measures and medication dosing were recorded, and adherence was calculated as the proportion of doses taken during the expected treatment duration. Factors associated with adherence were examined using logistic regression. A total of 242 individuals commenced DAA therapy, of whom 79 (32%) received enhanced adherence support. Enhanced support was associated with homelessness, daily injecting, Aboriginality, mental health co-morbidity and poly-drug use (all P < .001). Overall adherence was 86%, and 92% of patients missed one or more doses (median 10, IQR 4–24). At least 90% adherence during planned duration was seen in 38%, but increased to 66% by continuing therapy beyond planned duration. Intention-to-treat SVR12 was 68% and 66% in the enhanced adherence support sub-population, with 29% lost to follow-up by SVR12 testing. There were only 2 (0.8%) documented virological failures. Per-protocol SVR12 was 99% and 96% in the enhanced adherence support sub-population. In conclusion, adherence support may benefit those with multiple markers of marginalization. Extension of therapy beyond planned duration is a pragmatic strategy to enhance completion. Strategies to improve follow-up, particularly post-treatment are required.

Introduction

The advent of highly effective direct-acting antiviral (DAA) therapy for chronic hepatitis C virus (HCV) infection was the impetus for the World Health Organization to launch a strategy to eliminate HCV as a major public health threat by 2030. Specific targets include an 80% reduction in new infections, a 65% reduction in HCV-related deaths and 80% of the eligible population treated.[1] People who inject drugs (PWID) are the key population requiring upscaling of treatment to achieve elimination targets in many countries. Treating 8% of PWID per year in Australia should reduce HCV prevalence tenfold over a 15-year timeframe.[2,3]

Current PWID were less likely to undergo interferon-based treatment.[4–9] Barriers to HCV treatment uptake included stigma and discrimination within the health system, unstable housing and potential toxicity, particularly neuropsychiatric.[4,5] Integrated and multidisciplinary approaches, low threshold access and comprehensive care have improved HCV treatment uptake and adherence.[4,5]

In the era of DAAs, initial studies, including clinical trials, have documented favourable treatment adherence and outcomes amongst both people receiving opioid agonist treatment (OAT) and those with current injecting drug use.[10–15] Despite these findings, barriers continue for PWID populations. DAA restrictions related to ongoing drug use remain in many settings,[16] and clinician concerns around treatment adherence and HCV reinfection persist.[17,18] Further data are therefore required to understand HCV treatment adherence and dosing support requirements in real-world settings including amongst current PWID and other highly marginalized populations such as clients with unstable housing.

In Australia, government-funded DAA therapy has been available since March 2016, without liver disease stage, drug use or prescriber restrictions. The Kirketon Road Centre in Sydney provides a multidisciplinary approach to HCV treatment[19] and has expanded its model of care since DAAs became available in Australia to provide enhanced support for clients during treatment.

The aim of this study was to evaluate DAA treatment support, adherence and outcomes, including predictors of low adherence amongst highly marginalized clients attending a low threshold primary healthcare service.

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