Clinical question
How effective are electronic cigarettes in helping smokers achieve long-term abstinence?
Bottom line
Electronic cigarettes (ECs) with nicotine, compared with placebo ECs, helped smokers to stop smoking long-term; they also increased the number of people who reduced their cigarette consumption by half. This corresponds with findings from placebo-controlled trials of nicotine replacement therapy (NRT).1 There was evidence from 1 trial that ECs may lead to similar quit rates at 6 months as NRT, but the confidence interval was wide. There was no evidence that using ECs at the same time as using regular cigarettes made people less likely to quit smoking. Common adverse effects were irritation of the mouth and throat. There was no evidence that short-term use (2 years or less) was associated with health risk.
Caveat
The quality of the evidence was rated as low due to the small number of trials, low event rates and wide confidence intervals around the estimates. There was no biochemical assessment of the actual reduction in smoking.
Context
ECs are electronic devices that heat a liquid – usually comprising propylene glycol and glycerol, with or without nicotine and flavours. These are stored in disposable or refillable cartridges or a reservoir and are transformed into an aerosol for inhalation. Since ECs appeared on the market in 2006, there has been a steady growth in sales. Smokers report using ECs to reduce the risks of smoking, but some healthcare organisations have been reluctant to encourage smokers to switch to ECs, citing lack of evidence of efficacy and safety.
Cochrane Systematic Review
McRobbie H et al. Electronic cigarettes for smoking cessation and reduction. Cochrane Reviews, 2014, Issue 12. Art. No.: CD010216.DOI: 10.1002/14651858. CD010216.pub2. This review contains 13 studies involving 3499 participants.
1. Stead LF et al. Cochrane Database of Systematic Reviews 2012, Issue 11.
Cochrane Systematic Reviews for primary care practitioners
Developed by the Cochrane Primary Care Field, New Zealand Branch of the Australasian Cochrane Centre at the Department of General Practice and Primary Health Care, University of Auckland and funded by the Ministry of Health and New Zealand Doctor. PEARLS are meant for educational use and not to guide clinical care. New Zealanders can access the Cochrane Library free via www.cochrane.org.nz
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