Electronic Cigarettes for Smoking Cessation: A Randomised Controlled Trial

Study Questions:

Are electronic cigarettes more effective than nicotine patches at assisting smokers to quit?


This was a randomized controlled superiority trial conducted in Auckland, New Zealand between Sept 6, 2011, and July 5, 2013. Smokers, 18 years of age or older who wanted to quit, were randomized to 16 mg nicotine e-cigarettes, nicotine patches (21 mg patch, one daily), or placebo e-cigarettes (no nicotine). Randomization was stratified by ethnicity, sex, and level of nicotine dependence. The intervention started at 1 week prior to quit day and continued to 12 weeks after the quit date. All subjects received low-intensity behavioral support via voluntary telephone counseling. The primary outcome was biochemically verified continuous abstinence at 6 months (exhaled breath carbon monoxide measurement <10 ppm), and the primary analysis was by intention to treat.


Of 1,293 people who were assessed, 657 were eligible for inclusion in the study: 289 to nicotine e-cigarette, 295 to patches, and 73 to placebo e-cigarette. At 6 months, verified abstinence was 7.3% (21 of 289) with nicotine e-cigarettes, 5.8% (17 of 295) with patches, and 4.1% (3 of 73) with placebo e-cigarettes. Participants’ baseline characteristics were evenly balanced between treatment groups. Loss to follow-up was 22%: 17% in the nicotine e-cigarettes group, 27% in the patches group, and 22% in placebo e-cigarettes group. The risk difference for nicotine e-cigarette vs. patches was 1.51 (95% confidence interval [CI], -2.49 to 5.51); for nicotine e-cigarettes versus placebo e-cigarettes 3.16 (95% CI, -2.29 to 8.61). Achievement of abstinence was substantially lower than anticipated for the power calculation; thus, there was insufficient statistical power to conclude superiority of nicotine e-cigarettes to patches or to placebo e-cigarette. Seven-day point prevalence suggested a difference in favor of nicotine e-cigarettes, but no significant difference was observed at 6 months. No significant differences in adverse events between groups were noted. In post-hoc analyses using a 5% noninferiority limit for the risk difference, nicotine e-cigarettes were at least as effective as patches.


The investigators concluded that e-cigarettes, with or without nicotine, were modestly effective at helping smokers to quit, with similar achievement of abstinence as with nicotine patches, and few adverse events. Further research is needed to establish the overall benefits and risks of e-cigarettes for smoking cessation.


Given the increasing popularity of e-cigarettes, further research related to both effectiveness in smoking cessation and the additive potential is warranted.

Clinical Topics: Prevention, Smoking

Keywords: New Zealand, Risk, Nicotine, Follow-Up Studies, Cardiovascular Diseases, Carbon Monoxide, Risk Assessment, Tobacco Use Disorder, Tobacco Use Cessation Products, Smoking Cessation, Smoking

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