Insights for successful recruitment of people who actively use heroin to a pharmacotherapy trial: A case study

Background: This paper reports on recruiting strategies in a study which aimed to examine the mechanism of intranasal oxytocin on cue-induced opiate craving and attentional bias in males using heroin in addition to substitute opiates from four UK community drug treatment services.
Methods: Recruitment took place during and post-COVID-19 periods of social distancing and lockdowns. Caseworkers obtained consent to contact from interested service users before an initial telephone screen. People were then scheduled for in-person screens, typically within seven days of the initial telephone call. Subsequent visits took place within 30 days of the previous visit. Each visit lasted one hour and participants received one £20 voucher per completed visit.
Results: Thirty participants were randomized from 113 referrals. We were unable to contact 36% (n = 41) of people. Of those eligible to start the study (n = 44), 68% (n = 30) agreed to start the study, retaining 82% (n = 24) to completion. Factors which positively influenced recruitment were having a research
presence on site, the cultivation of relationships and demonstrating respect and gratitude toward the participants.
Conclusions: These results support the feasibility of recruiting males currently using heroin in addition to substitute opiates utilizing a person-first approach with service users and staff.