Synthesising evidence on e-cigarettes: two living systematic reviews exploring their efficacy and safety for smoking cessation, and how to stop using them

BACKGROUND Smoking is the leading preventable cause of cancer in the UK. Supporting people who smoke to quit is central to cancer care and prevention.

A high degree of uncertainty persists surrounding optimal use of e-cigarettes to help people quit smoking, and conclusions are likely to change as new evidence emerges.

AIMS To map and synthesise up-to-date evidence on e-cigarettes to inform policy, clinical, and personal decisions, to help prevent cancer and tackle health inequalities. We will seek to achieve this through three objectives: 1.

Regular updates of the existing Cochrane living systematic review (LSR) of e-cigarettes for smoking cessation and a map of this evidence, incorporating a new network meta-analysis, new research questions, and new analyses reflecting evolving research priorities 2.

Publish and maintain a new LSR of interventions for quitting e-cigarettes and associated evidence gap map, with a focus on both vaping and smoking outcomes 3.

Disseminate this evidence to inform policy decisions, clinical practice, and the choices of people who smoke and/or vape METHODS LSRs involve monthly searches for evidence and are updated regularly to ensure they are responsive to the needs of decision-makers. Searches, screening, data extraction and critical appraisal will follow standard Cochrane methods.

Every month, review statuses will be updated to highlight whether new evidence has been found and monthly briefing documents will be disseminated.

Analyses and the full-text of reviews will be updated when new data is likely to change or strengthen conclusions; approximately every three to four months. Members of the public will help shape the methods and review monthly updates. Evidence gap maps will map evidence by key questions and population groups, and identify where more research is needed.

HOW THE RESULTS OF THIS RESEARCH WILL BE USED Working closely with CRUK, our core aim is to ensure that regularly updated information is as useful as possible, particularly for contributing to policy.

In addition to regular review updates, planned outputs include “at a glance” monthly briefing documents; a webpage allowing easy access to new evidence; monthly podcasts summarising new evidence; and webinars to coincide with updates.

At project end, we will review the impact and stability of the evidence base, to inform the future update schedule of the reviews.