E-cigarettes versus nicotine replacement treatment as harm reduction interventions for smokers who find quitting difficult: randomized controlled trial

Background and aims The majority of smokers accessing the current best treatments continue to smoke. We aimed to test if e-cigarettes (EC) compared with nicotine replacement treatment (NRT) can help such smokers to reduce smoking. Design Randomized controlled trial of EC (n = 68) versus NRT (n = 67) with 6-month follow-up. Setting Stop smoking service in London, UK. Participants A total of 135 smokers (median age = 40 years, 51% male) previously unable to stop smoking with conventional treatments. Interventions Participants received either NRT of their choice (8-week supply) or an EC starter pack and instructions to purchase further e-liquids of strength and flavours of their choice themselves. Products were accompanied by minimal behavioural support. Measurements Participants who reported that they stopped smoking or reduced their daily cigarette consumption by at least 50% at 6-month follow-up were invited to provide a carbon monoxide (CO) reading. The primary outcome was biochemically validated reduction in smoke intake of at least 50% at 6 months and the main secondary outcome was sustained validated abstinence at 6 months. Drop-outs were included as 'non-reducers'. Findings Validated smoking reduction (including cessation) was achieved by 26.5 versus 6.0% of participants in the EC and NRT study arms, respectively [relative risk (RR) = 4.4, P = 0.005, 95% confidence interval (CI) = 1.6-12.4]. Sustained validated abstinence rates at 6 months were 19.1 versus 3.0% (RR = 6.4, P = 0.01, 95% CI = 1.5-27.3). Product use was high and equal in both study arms initially, but at 6 months allocated product use was 47% in the EC arm versus 10% in the NRT arm (chi(2)((1)) = 22.0, P < 0.001), respectively. Adverse events were minor and infrequent. Conclusions In smokers unable to quit using conventional methods, e-cigarettes were more effective than nicotine replacement therapy in facilitating validated long-term smoking reduction and smoking cessation when limited other support was provided.