Electronic Cigarettes vs Varenicline for Smoking Cessation in Adults: A Randomized Clinical Trial

Importance: Little is known about the relative effectiveness of nicotine-containing electronic cigarettes (ECs) compared with varenicline as smoking cessation aids.

Objective: To determine the relative effectiveness of ECs in smoking cessation.

Design, setting, and participants: This randomized placebo-controlled single-center trial was conducted in northern Finland. Participants aged 25 to 75 years who smoked daily and had volunteered to quit smoking were recruited from August 1, 2018, to February 20, 2020, via local media. The trial included 52 weeks of follow-up. All data analyses were conducted from September 1, 2022, to January 15, 2024. The participants, study nurses, and researchers were masked to group assignment.

Intervention: The participants were assigned by block randomization to receive 18 mg/mL of nicotine-containing ECs together with placebo tablets, varenicline with standard dosing together with nicotine-free ECs, or placebo tablets together with nicotine-free ECs, all combined with a motivational interview, with the intervention phase lasting for 12 weeks.

Main outcome and measure: The primary outcome was self-reported 7-day conventional cigarette smoking abstinence as confirmed by the exhaled carbon monoxide level on week 26. The analysis followed the intent-to-treat principle.

Results: Of the 561 recruited participants, 458 (81.6%) eligible participants (257 women [56%]; 201 men [44%]; mean [SD] age, 51 [11.6] years) were randomized. The primary outcome occurred in 61 of 152 participants (40.4%) in the EC group, 67 of 153 (43.8%) in the varenicline group, and 30 of 153 (19.7%) in the placebo group (P < .001). In the pairwise comparison, placebo differed statistically significantly from ECs (risk difference [RD], 20.7%; 95% CI, 10.4-30.4; P < .001) and varenicline (RD, 24.1%; 95% CI, 13.7-33.7; P < .001), but the difference was statistically insignificant between ECs and varenicline (RD, 3.4%; 95% CI, -7.6 to 14.3; P = .56). No serious adverse events were reported.

Conclusions: This randomized clinical trial found that varenicline and nicotine-containing ECs were both effective in helping individuals in quitting smoking conventional cigarettes for up to 6 months.