E-cigarettes to Augment Stop Smoking In-person Support and Treatment with varenicline (E-ASSIST): a pragmatic randomised controlled trial.

ABSTRACT

BACKGROUND: We examined whether, in adults receiving behavioural support, offering e-cigarettes together with varenicline helps more people stop smoking cigarettes than varenicline alone. METHODS: A two-group, parallel-arm, pragmatic randomised controlled trial was conducted in six English stop smoking services from 2019-2020. Adults enrolled onto a 12-week programme of in-person one-to-one behavioural smoking cessation support (N=92) were randomised to receive either (i) a nicotine e-cigarette starter-kit alongside varenicline or (ii) varenicline alone. The primary outcome was biochemically-verified abstinence from cigarette smoking between weeks nine-to-12 post quit-date, with those lost to follow-up considered not abstinent. The trial was stopped early due to COVID-19 restrictions and a varenicline recall (92/1266 participants recruited). RESULTS: Nine-to-12-week smoking abstinence rates were 47.9% (23/48) in the e-cigarette-varenicline group compared with 31.8% (14/44) in the varenicline-only group, a 51% increase in abstinence among those offered e-cigarettes; however, the confidence interval (CI) was wide, including the possibility of no difference (risk ratio [RR]=1.51, 95%CI=0.91-2.64). The e-cigarette-varenicline group had 43% lower hazards of relapse from continuous abstinence than the varenicline-only group (hazards ratio [HR]=0.57, 95%CI=0.34-0.96). Attendance for 12 weeks was higher in the e-cigarette-varenicline than varenicline-only group (54.2% versus 36.4%; RR=1.49, 95%CI=0.95-2.47), but similar proportions of participants in both groups used varenicline daily for ≥8 weeks after quitting (22.9% versus 22.7%; RR=1.01, 95%CI=0.47-2.20). Estimates were too imprecise to determine how adverse events differed by group. CONCLUSION: Tentative evidence suggests offering e-cigarettes alongside varenicline to people receiving behavioural support may be more effective for smoking cessation than varenicline alone. IMPLICATIONS Offering e-cigarettes to people quitting smoking with varenicline may help them remain abstinent from cigarettes, but the evidence is tentative because our sample size was smaller than planned - caused by COVID-19 restrictions and a manufacturing recall. This meant our effect estimates were imprecise, and additional evidence is needed to confirm that providing e-cigarettes and varenicline together helps more people remain abstinent than varenicline alone.