Evaluating the effectiveness of e-cigarettes compared with usual care for smoking cessation when offered to smokers at homeless centres: protocol for a multi-centre cluster-randomized controlled trial in Great Britain.

Introduction:
This text is a study protocol for a multi-center cluster-randomized controlled trial in Great Britain, evaluating the effectiveness of e-cigarettes compared with usual care for smoking cessation in homeless centers. The study will provide evidence for treatment efficacy in this population and test the offer of e-cigarettes as a smoking cessation aid.

Key Points:

* The study is a two-arm multi-center cluster-randomized controlled trial with mixed-method embedded process and economic evaluations.
* The trial will take place in 32 homeless centers across five areas of Great Britain.
* Participants will be adult smokers, aged 18+, known to center staff and willing to consent.
* The intervention arm will receive an e-cigarette starter pack with weekly allocations of nicotine-containing e-liquid for four weeks, while the control arm will receive usual care, which comprises very brief advice and a leaflet signposting to the local stop smoking service.
* The primary outcome is 24-week sustained carbon monoxide-validated smoking cessation, and secondary outcomes include 50% smoking reduction, 7-day point prevalence quit rates, changes in risky smoking practices, cost-effectiveness, fidelity of intervention implementation, mechanisms of change, contextual influences, and sustainability.
* The study is funded by the National Institute for Health Research, Public Health Research Programme.
* The authors are from various institutions across Great Britain.

Main Message:
The study aims to address the urgent public health need to improve the lives of people experiencing homelessness, who have a significantly higher smoking prevalence rate than the housed population. The study will evaluate the offer of e-cigarettes as a smoking cessation aid in this population and provide evidence for treatment efficacy. The results will be used to inform the larger-scale implementation of offering e-cigarettes throughout homeless centers to aid smoking cessation.

Cox S, Bauld L, Brown R, et al. Evaluating the effectiveness of e-cigarettes compared with usual care for smoking cessation when offered to smokers at homeless centres: protocol for a multi-centre cluster-randomized controlled trial in Great Britain. Addiction (Abingdon, England). 2022;117(7):2096-2107. doi:10.1111/add.15851