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Am Fam Physician. 2019;100(7):442

Clinical Question

Are e-cigarettes an effective way to help patients quit smoking?

Bottom Line

Among adults who smoked a median of 15 cigarettes per day, those who were randomized to receive e-cigarettes were more likely to be abstinent at one year than those who received nicotine replacement (number needed to treat [NNT] = 12). They also had less cough and phlegm production. (Level of Evidence = 1b)


Many physicians have had patients who claimed to have stopped smoking by switching to e-cigarettes. But is this switch truly effective, and how durable are the effects? In this trial, adult smokers in the United Kingdom were recruited via social media and randomized to receive nicotine replacement or e-cigarettes. All participants were not currently using either approach and expressed no preference. Those randomized to use nicotine replacement could choose their preferred method, including nasal spray, inhaler, mouth spray, microtabs, gum, or patch. Those randomized to use e-cigarettes received a starter kit and were encouraged to experiment with different flavors and strengths of e-liquids. The median age of participants was 41 years, approximately one-half were women, and the median number of cigarettes smoked per day was 15. Groups were balanced at the beginning of the study, and a total of 884 patients were randomized. The primary outcome, evaluated using the intention-to-treat principle, was self-reported abstinence confirmed by a carbon monoxide level of less than 8 ppm at one year. This occurred for 18% in the e-cigarette group and 9.9% in the nicotine replacement group (P < .05; NNT = 12). Short-term abstinence at four weeks was also higher with the use of e-cigarettes (43.8% vs. 30.0%; P < .05; NNT = 7). Respiratory symptoms of cough and phlegm were somewhat less common among those in the e-cigarette group at 52 weeks. There was no difference in adverse events between groups, with nausea more common in the nicotine replacement group (number needed to treat to harm [NNTH] = 16) and throat irritation more common in the e-cigarette group (NNTH = 7). A total of 40% of the patients in the e-cigarette group were still using e-cigarettes at one year, so they were still hooked on nicotine, just not tobacco.

Study design: Randomized controlled trial (nonblinded)

Funding source: Government

Allocation: Concealed

Setting: Outpatient (any)

Reference: Hajek P, Phillips-Waller A, Przulj D, et al. A randomized trial of e-cigarettes versus nicotine-replacement therapy. N Engl J Med. 2019;380(7):629–637.

Editor's Note: See related article and online comment from the author regarding recent adverse events related to e-cigarette use at

Dr. Ebell is Deputy Editor for Evidence-Based Medicine for AFP and cofounder and Editor-in-Chief of Essential Evidence Plus, published by Wiley-Blackwell.

POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, see Copyright Wiley-Blackwell. Used with permission.

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