Efficacy and safety of e-cigarette use for smoking cessation: a systematic review and meta-analysis of randomized controlled trials

Abstract

Abstract Background Quitting smoking substantially reduces the risk of developing cardiovascular disease. Smokers are increasingly turning to electronic cigarettes (e-cigarettes) to help them quit smoking combustible cigarettes. However, the efficacy and safety of e-cigarettes for smoking cessation remain controversial. Purpose To examine the efficacy and safety of e-cigarette use for smoking cessation. Methods We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing nicotine and non-nicotine e-cigarettes (alone, or in combination with behavioural and/or pharmacological interventions) to conventional smoking cessation therapies (pharmacological, behavioural, or both). We systematically searched MEDLINE, Embase, and the Cochrane Libraries. Inclusion was restricted to RCTs that reported biochemically validated abstinence at six months or greater. The primary comparison was nicotine e-cigarettes versus any (non-e-cigarette) conventional smoking cessation therapy. Count data were pooled using DerSimonian and Laird random-effects models with inverse variance weighting to obtain relative risks (RRs) and 95% confidence intervals (CIs). Results A total of six RCTs (n=3,401) were included, with maximum follow-up durations ranging from six to 12 months. Compared with conventional smoking cessation therapies, point estimates favoured nicotine e-cigarettes for the most rigorous criterion of abstinence, continuous abstinence, and point prevalence abstinence, although findings were inconclusive due to wide 95% CIs (Table 1). Similar trends were observed when comparing non-nicotine e-cigarettes to traditional smoking cessation therapies. Compared with non-nicotine e-cigarettes, nicotine e-cigarettes increased abstinence as defined by the most rigorous criterion. Although there was a signal suggesting a potential increased risk of respiratory adverse events with nicotine e-cigarettes versus traditional therapies, the 95% CI is wide. Conclusion E-cigarettes appear to be more efficacious than conventional nicotine pharmacotherapies and behavioural smoking cessation therapies. Although currently available safety data are inconclusive, e-cigarettes may be considered for smoking cessation given the established long-term health consequences of continued smoking. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Mr. Levett is supported by an Ivan Racheff Scholarship, funded through the McGill University Faculty of Medicine and Health Sciences Research Bursary Program. Dr. Filion is supported by a Senior Research Scholar award from the Fonds de recherche du Québec – Santé and a William Dawson Scholar award from McGill University.