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Willingness of people who inject drugs to participate in a randomised controlled trial involving financial incentives to initiate hepatitis C treatment

https://doi.org/10.1016/j.drugalcdep.2022.109438Get rights and content

Highlights

  • Most participants were willing to participate in a randomised controlled trial with financial incentives.

  • Willingness to participate in a randomised controlled trial increased by financial amount offered.

  • The preferred method of incentive distribution over three clinical visits was receiving the entire incentive at first visit.

Abstract

Background

Evidence regarding the acceptability of contingency management is limited. We investigated the willingness of people who inject drugs to participate in a randomised controlled trial (RCT) involving financial incentives to initiate HCV treatment.

Methods

ETHOS Engage is an observational cohort study of people with a history of injecting drug use who either injected in the past six months or receive opioid agonist therapy (OAT) in Australia. We assessed willingness to participate in a RCT with financial incentives and factors associated with preference for entire incentive ($60) at first clinic visit versus delayed incentive with logistic regression.

Results

93% (593/635) of eligible participants agreed to participate in an RCT with financial incentives of which 24% were Aboriginal or Torres Strait Islander, 84% had completed secondary school, and 59% injected drugs in the prior month. Willingness to participate in an RCT increased by amount offered: unspecified (72%), $20 (75%), $60 (80%), and $100 (85%). The preferred incentive distribution method over three clinical visits was entire incentive at first clinical visit (32%). Among those with a preferred distribution method (n = 369), factors associated with entire incentive at first clinic visit were being Aboriginal or Torres Strait Islander (aOR 1.75; 95% CI 1.05–2.94), completion of secondary school (aOR 0.46; 95% CI 0.26–0.83) and mainly injected heroin in month prior (aOR 1.82; 95% CI 1.03–3.20).

Conclusion

Most participants were willing to participate in an RCT involving financial incentives to initiate treatment but differed regarding distribution. Study findings inform implementation of incentives in clinical practice.

Introduction

Globally, ~58 million persons have chronic hepatitis C virus (HCV) infection (World Health Organization, July, 2021). The development of interferon-free, direct-acting antivirals (DAAs) has transformed the treatment landscape with sustained virologic responses (SVR) of > 95%, minimal side effects, and limited drug-drug interactions for all genotypes (AASLD-IDSA, 2018, European Association for the Study of the Liver, 2018). People who inject drugs (PWID) constitute a substantial proportion of overall cases in North America, Latin America, and Eastern Europe (Grebely et al., 2019, Hajarizadeh et al., 2013) but historically have had low HCV treatment uptake (Grebely et al., 2009, Mehta et al., 2008). In Australia, there has been considerable uptake of HCV treatment among PWID since unrestricted access to government funded DAAs became available in March 2016, still, the majority of PWID have not received treatment (Iversen et al., 2019, Iversen et al., 2017). Evidence on the acceptability of innovative strategies to enhance linkage into HCV care among PWID is needed to increase treatment uptake.

Contingency management (CM) is the reward (or removal) of an incentive, most often financial, to influence targeted responses in behaviours (Giles et al., 2014). CM has been studied with multiple health behaviours – e.g., tobacco cessation (Etter and Schmid, 2016, Volpp et al., 2009), breastfeeding (Relton et al., 2018), weight loss (Volpp et al., 2008), glycemic control (Long et al., 2012), HBV vaccination (Topp et al., 2013, Weaver et al., 2014), and HIV testing, linkage to care, and treatment adherence (Bassett et al., 2015, El-Sadr et al., 2017) – and in select studies, has demonstrated favourable outcomes for clients with substance use dependence (Bolivar et al., 2021, Giles et al., 2014, Herrmann et al., 2017, Lagarde et al., 2009, Prendergast et al., 2006, Shoptaw et al., 2005). Although the use of CM to increase HCV treatment uptake among PWID has been investigated (Sulkowski et al., 2017, Wohl et al., 2017) there is limited evidence regarding acceptability among clients (Getty et al., 2021, Srebnik et al., 2013). The study aim was to investigate the willingness of PWID to participate in a RCT involving financial incentives to initiate HCV treatment.

Section snippets

Study design and population

The Enhancing Treatment of Hepatitis C in Opioid Substitution Settings (ETHOS) Engage is an observational cohort study in Australia involving PWID attending drug treatment clinics and needle and syringe programs (Valerio et al., 2021). ETHOS Engage study clinics (n = 21) participating in Wave 2 of the study were given information about an RCT involving CM (financial incentives in the form of a voucher) to enhance linkage to HCV treatment. Collectively, 12 drug treatment clinics in New South

Results

Compared to participants at non-CM ETHOS Engage sites (n = 576), participants at CM study sites (n = 635) were less likely to report injection drug use in the past month (43% vs 28%, p < 0.001), and less likely to be homeless (7% vs 11%, p = 0.032). At CM pilot sites, 93% (593/635) of participants were eligible and consented to take part in the pilot study. Compared to those who declined or were not eligible (n = 42), participants who agreed to take part in the CM pilot (n = 593) were more

Discussion

Despite multiple studies investigating the use of CM among people with substance dependence (Bolivar et al., 2021), there is limited evidence regarding the acceptability of CM (Getty et al., 2021, Srebnik et al., 2013), particularly in the HCV treatment field (Sulkowski et al., 2017, Wohl et al., 2017). Findings from this pilot study indicated high willingness among participants to take part in an RCT involving financial incentives to initiate HCV treatment, however, participants differed in

CRediT authorship contribution statement

All authors contributed to the study conception and design, data collection and management, and contributed valuable input to the draft of the manuscript. David Silk is the ETHOS study coordinator. Alison D. Marshall, Anna Conway, Evan B. Cunningham, Heather Valerio, Gregory J. Dore, and Jason Grebely developed a data analysis plan. Alison D. Marshall, Evan B. Cunningham, Heather Valerio, Gregory J. Dore, and Jason Grebely assisted with the data analysis. Anna Conway conducted the study

Conflict of Interest

Alison D. Marshall has nothing to declare. Gregory J. Dore is a consultant/advisor and has received research grants from Merck, Gilead, and AbbVie outside the submitted work. Jason Grebely is a consultant/advisor and has received research grants from AbbVie, Camurus, Cepheid, Gilead, Hologic, Indivior, and Merck outside the submitted work. All other authors had nothing to declare.

Acknowledgements

The authors thank all participants who took part in the ETHOS Engage study. We first give special acknowledgement to the following peer workers and organisations who helped invaluably with participant recruitment in ETHOS Engage Wave 1 and Wave 2:

The NSW Users and AIDS Association (NUAA): Sara Adey, Rodd Hinton, Melanie Joyce, Cheryl Woods, Alain Jenart, Hope Everingham, Louisa Jansen, Lucy Pepolim.

Youth Link Needle and Syringe Program, Cairns: Kathy Clark.

Hepatitis South Australia: Lisa

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