Electronic cigarettes (ECs) are as effective as varenicline and more effective than nicotine chewing gum in helping smokers to quit cigarettes, according to recent findings.¹

These findings resulted from a randomized clinical trial conducted in China, designed to expand upon the limited data on e-cigarette effectiveness compared to nicotine replacement therapy (NRT). The research was led by Zhao Liu, PhD, from the department of tobacco control and prevention of respiratory disease at the China-Japan Friendship Hospital’s Center of Respiratory Medicine in Beijing.

The investigators led by Liu added that no information was shown to exist on how e-cigarette efficacy compared to that of varenicline among smokers attempting to quit. They sought to contribute to this lack of data as well.

“The study was conducted in China, where access to and use of stop-smoking medications, as well as ECs, are much lower than in Western countries,” Liu and colleagues wrote. “This had the potential advantages of lower expectancy effects and reduced risk of trial arms contamination via use of non-allocated products, an issue that affected a recent UK trial of ECs vs NRT as treatments for pregnant smokers.”²

Background and Methods

The investigators conducted the randomized clinical trial at several different centers using 3 study arms, implementing an open-label design. The research encompassed 7 total sites, mainly hospitals, and utilized several recruitment channels such as trial sites, community events, local newspapers, different websites, and referrals from other medical institutions.

The research team determined their criteria for inclusion would be those those who smoked 10 cigarettes or more per day for 5 years minimum, those aged 25 - 45 years, those motivated to quit smoking, and those with an expired air carbon monoxide reading of 9 parts per million (ppm) or greater.

Exclusion criteria included pregnancy or breastfeeding, use of stop-smoking medication in recent times, extended use of electronic cigarette history, severe psychiatric issues, reluctance to use the necessary products, and a current diagnosis of cancer or remission for lower than a year.

Prospective subjects were told to contact local study sites after which those deemed eligible would attend a baseline visit where they would provide a carbon monoxide reading, discussed details, sign for consent, fill out questionnaires, and set a target quit date, (typically scheduled 2 weeks after this meeting).

The investigators randomly assigned subjects to 1 of 3 interventions. These individuals were suggested to join a WeChat group for motivational support and go to monthly visits at the study center for half a year. During each meeting, study forms were filled out, and carbon monoxide readings were gathered.

The interventions used by the research team involved use of either a cartridge-based e-cigarette (30 mg/mL nicotine salt for 2 weeks and 50 mg/mL in the following weeks), 2 mg (for smokers of ≤20 cigarettes each day) or 4 mg (>20 cigarettes each day) nicotine gum, or varenicline (0.5 mg once each day for 3 days; 0.5 mg twice a day for 4 days; and 1 mg twice per day thereafter). The participants were given 1 of these options for 12 weeks total with minimal behavioral support.

The main outcome assessed by the team was sustained abstinence from smoking at the half-year mark, validated by an expired-air carbon monoxide reading. Individuals lost to follow-up were labeled as non-abstainers in their analysis.

Findings

There were 1068 participants, 33.5% of which were female and which had a mean age of 33.9 years. The investigators randomized 38.3%, 38.3%, and 23.4% to be in the e-cigarette, varenicline, and nicotine gum cohorts, respectively.

The 6-month biochemically validated abstinence rates seen by the investigators were reported to be 15.7% in the e-cigarette arm, 14.2% in the varenicline, and 8.8% in the nicotine gum. The quit rate for e-cigarette participants was shown to be noninferior to that of the varenicline arm (absolute risk reduction, 1.47%; 95% CI, −1.41% to 4.34%) and shown to be higher than that of the nicotine gum arm (odds ratio, 1.92; 95% CI, 1.15-3.21).

The investigators found that adherence to the different programs was shown to be similar for the first 3 months of research, but they found that the 62.8% of those in the e-cigarette arm continued use of the products at 6 months.

The most common adverse reactions observed by the research team included throat and mouth irritation in the e-cigarette cohort, nausea for varenicline, and throat and mouth irritation in the nicotine gum cohort. They identified no serious adverse events during their research.

“To see whether public health messages on EC use for smoking cessation need to include advice to use any additional support, further studies are needed that compare effects of different levels of behavioral support added to ECs,” they wrote. “The current trial results may help to clarify another question concerning previous trials. Most participants in stop-smoking trials in the West have previous experience with stop-smoking medications.”

References

1. ^{Lin H, Liu Z, Hajek P, et al. Efficacy of Electronic Cigarettes vs Varenicline and Nicotine Chewing Gum as an Aid to Stop Smoking: A Randomized Clinical Trial. JAMA Intern Med. Published online January 29, 2024. doi:10.1001/jamainternmed.2023.7846.}
2. ^{Hajek P, Przulj D, Pesola F, et al. Electronic cigarettes versus nicotine patches for smoking cessation in pregnancy: a randomized controlled trial. Nat Med. 2022;28(5):958-964. doi:10.1038/s41591-022-01808-0.}