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Review
. 2021 Nov 22:7:69.
doi: 10.18332/tpc/143077. eCollection 2021.

Efficacy and safety of electronic cigarettes as a smoking cessation intervention: A systematic review and network meta-analysis

Joan M Quigley  1   2 , Cathal Walsh  3 , Caitriona Lee  1 , Jean Long  1 , Helen Kennelly  1 , Anne McCarthy  1 , Paul Kavanagh  4   5
Affiliations
Review

Efficacy and safety of electronic cigarettes as a smoking cessation intervention: A systematic review and network meta-analysis

Joan M Quigley et al. Tob Prev Cessat. .

Abstract

Introduction: This systematic review of randomized controlled trials (RCTs) evaluated the efficacy and safety of electronic cigarettes (e-cigarettes, ENDS) in helping people who smoke to achieve abstinence compared with electronic non-nicotine delivery systems (ENNDS, no nicotine) or any smoking cessation comparator treatment or combination of treatments at 24-26 weeks and at 52 weeks.

Methods: Systematic review techniques involved searches of three databases in February 2020 with update searches run on 14 May 2021, two-person independent screening, two-person independent assessment of bias, formal extraction of data with verification by a second person, a feasibility assessment to decide if meta-analysis was appropriate, and network meta-analysis (NMA) of data at 24-26 weeks. Data at 52 weeks were narratively summarized.

Results: Ten RCTs met the inclusion criteria, eight for efficacy and ten for safety. Eight of the nine RCTs were assessed as at high risk of bias. The sample sizes of the RCTs were 30-2012. Using nicotine replacement therapy (NRT) as the reference treatment, the incidences of smoking cessation at 24-26 weeks were comparable between ENDS and NRT groups (RR=1.17; 95% CrI: 0.66-1.86). Three sensitivity analyses were carried out indicating the main findings for 24-26 weeks were robust to assumptions. The findings at 52 weeks were inconclusive.

Conclusions: This systematic review and NMA indicates that there is no clear evidence of a difference in effect between nicotine containing e-cigarettes and NRT on incidences of smoking cessation at 24-26 weeks, and substantial uncertainty remains.

Keywords: e-cigarettes; network meta-analysis; smoking cessation; systematic review.

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Conflict of interest statement

The authors have each completed and submitted an ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors declare that they have no competing interests, financial or otherwise, related to the current work. P. Kavanagh reports unpaid role as Chair Guideline Development at Group-National Stop Smoking, the National Stop Smoking Guidelines reference HRB project upon which this paper was based on (https://www.hrb.ie/publications/publication/electronic-cigarette-and-smoking-cessation-an-evidence-review/).

Figures

Figure 1
Figure 1
Risk of bias in ENDS trials
Figure 2
Figure 2
Evidence network for smoking cessation at 24 or 26 weeks
Figure 3
Figure 3
Network meta-analysis of smoking cessation at 24 or 26 weeks
See this image and copyright information in PMC

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