Accelerated Partner Therapy contact tracing intervention for people with chlamydia: the LUSTRUM process evaluation using programme theory

BackgroundUsing programme theory we report a process evaluation of Accelerated Partner Therapy (APT) - a novel contact tracing (partner notification) intervention for people with chlamydia as part of the LUSTRUM trial. MethodsFollowing the specification and visualisation of initial programme theory, questions of context dependency, fidelity, and functioning of putative intervention mechanisms were addressed using deductive thematic analysis of qualitative data collected through focus groups and individual interviews with purposively sampled health care professionals (n=34 from ten sites), index patients (n=15), and sex partners who received APT (n=17). Analyses were independent of trial results. ResultsAPT was anticipated to change key interactions and sexual health service organisation to accommodate safe and optimal remote care. APT training and resources transformed key interactions as anticipated. Overall intervention fidelity was good and APT was well-liked by those who delivered and received it. Putative intervention mechanisms worked mostly as expected although those concerned with local implementation sometimes worked counter to expectations. APT and its trial struggled to be implemented at scale across all sites. Considerable pressures drove services to constantly adapt to achieve efficiencies. APT was perceived as time consuming without visible impact on perceived patient numbers in clinic curtailing positive feedback loops driving normalisation. DiscussionUsing programme theory we show an evidence-based, theoretically informed, overview of how APT worked dynamically within the context of the trial and within UK sexual health services. We find a mixed picture of a well-liked, intuitive, coherent intervention struggling to gain purchase within an already pressured service. Trial registrationISRCTN15996256 Study protocoldoi.org/10.1136/bmjopen-2019-034806 Ethical approvalThis study received ethical approval from London--Chelsea Research Ethics Committee (18/LO/0773). Findings will be published with open access licences. FundingThis work presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (reference number RP-PG-0614-20009).