Review of: Hajek P et al, N Engl J Med 2019;380(7):629–637

E-cigarettes are increasingly popular, often touted as exposing users to fewer toxins than combustible cigarettes. Might they be useful for smoking cessation and abstinence? To answer this question, Hajek et al performed a multicenter randomized controlled trial comparing e-cigarettes to nicotine-replacement therapy (NRT) in adults seeking help to quit smoking.

Participants were recruited through a smoking cessation program in the United Kingdom. Of the 2045 screened, 886 participants (median age 41 years, 51.8% male, average of 15 cigarettes per day) were enrolled in the study based on not having a strong preference for e-cigarettes or NRT and not currently using either product. They were then randomized to receive either an e-cigarette or NRT, and asked not to use the non-assigned product.

Those in the e-cigarette group were given an e-cigarette and bottle of tobacco-flavored e-liquid containing 18 mg/mL of nicotine, and directed to purchase their own future e-liquid. Those in the NRT group were offered their preferred product; most participants chose the patch combined with the gum.

At baseline, 4 weeks, and 1 year, participants completed trial visits in which carbon monoxide levels (a proxy for combustible cigarette consumption) were checked. Most participants (78.8%) completed the 1-year follow-up. Dropouts were classified as not being abstinent. The primary outcome measured was sustained abstinence at 1 year. Secondary outcomes included reported treatment usage, perceptions of assigned products, and respiratory symptoms.

Abstinence rates were higher in the e-cigarette group at all time points. The e-cigarette group achieved a 1-year abstinence rate of 18.0%, compared with 9.9% in the NRT group (RR 1.83, CI 1.30–2.58). Among all participants who did not achieve abstinence, those in the ­e-cigarette group also had higher rates of reduced smoking (RR 1.75, CI 1.12–2.72). The authors speculated that ­e-cigarettes were more effective because they better alleviated tobacco withdrawal and allowed for greater tailoring of treatment dose.

There was a higher rate of product usage in the e-cigarette group than in the NRT group: 39.5% and 4.3% at the end of the 1-year study period, respectively. This difference was even greater among participants with 1 year of abstinence (80% vs 9%). E-cigarettes were rated higher than nicotine replacement in terms of providing satisfaction and reducing urges to smoke.

Interestingly, regarding respiratory symptoms, the e-cigarette group had less cough and phlegm than the NRT group, and both groups were similar regarding incidence of wheezing and shortness of breath.

CATR’s Take
Smoking cessation remains difficult, as demonstrated by the low success rate in this study regardless of the treatments rendered. E-cigarettes may be more efficacious than NRT for abstinence in those motivated to quit smoking. Still, given the risks associated with e-cigarettes—including vaping-associated illnesses, inhaling potentially toxic aerosols, and the possibility of burns from vaporizer devices—clinicians should use caution in recommending e-cigarettes as treatment. Clinicians should also be mindful of the CDC’s guidance, issued in February 2020, which states that patients choosing to use e-cigarettes for smoking cessation should completely switch from cigarettes to e-cigarettes and avoid an extended period of dual use. Further research is needed to compare e-cigarettes with other smoking cessation treatment modalities, including bupropion, varenicline, and behavioral treatments.