Factors influencing recruitment to a randomised placebo-controlled trial of oral naltrexone and extended release implant naltrexone: Qualitative study

Abstract

Aims: To understand the influences on recruitment to the Naltrexone Enhanced Addiction Treatment (NEAT) study, a randomised placebo-controlled trial of extended-release naltrexone (XR-NTX) implants for opioid use disorder (OUD), to learn lessons for the design and conduct of similar future research.

Methods: 29 face-to-face, semi-structured qualitative interviews were conducted with patients recruited to NEAT (n = 6), patients not recruited (n = 11), researchers who designed the trial (n = 5), and staff who delivered the trial (n = 7). The social marketing mix was used as a framework to guide the data analyses.

Results: Dimensions of the 7Ps of the social marketing mix - product, price, place, promotion, physical environment, people, and processes all influenced recruitment to the NEAT trial. Among other things, the potential to receive a naltrexone implant (product); the provision of transport passes and shopping vouchers (price); clear verbal explanations (promotion); familiarity of the trial setting (physical environment); and approachable, friendly and informative trial delivery staff (people) positively influenced recruitment. Whereas, wanting a less medical approach to recovery (product); the perceived time, physical, and psychological costs of taking part (price); service ideological opposition to naltrexone in recovery (place); inaccessible written information (promotion); the location and nature of the trial setting (physical environment); a lack of knowledge about implants (people); and the blind allocation and potential of placebo (processes) deterred people from joining the trial.

Conclusions: Qualitative research informed by the social marketing mix as an analytical framework yielded detailed insights into understanding the factors and circumstances that influenced recruitment to the NEAT trial. Our findings have implications for the planning and implementation of future addiction trials, especially trials of extended-release formulations.

Keywords: Clinical trial; Naltrexone; Opioid dependence; Qualitative; Social marketing; Study recruitment.