Abstract
Background
Reports of the effectiveness of e-cigarettes (ECs) for smoking cessation vary across different studies making implementation recommendations hard to attain. We performed a systematic review and meta-analysis to synthesise the current evidence regarding the effectiveness of ECs for smoking cessation.
Methods
PubMed, PsycInfo and Embase databases were searched for randomized controlled trials comparing nicotine ECs with non-nicotine ECs or with established smoking cessation interventions (nicotine replacement therapy (NRT) and or counselling) published between 01/01/2014 and 01/05/2019. Data from eligible studies were extracted and used for random-effects meta-analyses.
Results
Our literature review yielded 13190 publications with 10 studies being identified as eligible for systematic review, covering 8362 participants, and 8 for meta-analyses (n = 30 - 6006). Using the last follow-up of eligible studies, the proportion of smokers achieving abstinence was 1.67 [95CI:0.99 - 2.81] times higher in nicotine EC users compared to non-nicotine EC users. The proportion of abstinent smokers was 1.69 [95CI:1.25 - 2.27] times higher in EC users compared to participants receiving NRT. EC users showed a 2.70 [95CI:1.15 - 6.30] times higher proportion of abstinent smokers in comparison to participants solely receiving counselling.
Conclusions
Our analysis showed modest effects of nicotine-ECs compared to non-nicotine ECs. When compared to NRT or counselling, results suggest that nicotine EC may be more effective for smoking cessation. As ECs also help maintaining routinized behaviour and social aspects of smoking, we hypothesise that this may explain their advantage as a tool for smoking cessation. However, given the small number of included studies, different populations, heterogeneous designs, and the overall moderate to low quality of evidence, it is not possible to offer clear recommendations. More comparable data is needed to strengthen confidence in the quality of evidence.
Key messages
The number of previous studies assessing the effectiveness of ECs for smoking cessation is limited. Further, comparability of these studies is restricted, weakening the quality of evidence. Although current evidence on the effectiveness of ECs for smoking cessation is inconclusive, our meta-analyses suggest that ECs could be a promising alternative tool in attempts to achieve abstinence.
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