Aim

E-cigarettes, or nicotine vaping products, are potential smoking cessation aids that provide both nicotine and behavioural substitution for combustible cigarette smoking. This review aims to compare the effectiveness of nicotine e-cigarettes for smoking cessation with licensed nicotine replacement therapies (NRT) and nicotine-free based control conditions by using network meta-analysis (NMA).

Methods

We searched PubMed, Web of Science and PsycINFO for randomised controlled trials (RCTs) that allocated individuals to use nicotine e-cigarettes, compared to those that used licensed NRT (e.g., nicotine patches, nicotine gums, etc), or a nicotine-free control condition such as receiving placebo (nicotine-free) e-cigarettes or usual care. We only included studies of healthy individuals who smoked. Furthermore, we identified the latest Cochrane review on NRT and searched NRT trials that were published in similar periods as the e-cigarette trials we identified. NMA was conducted to compare the effect of e-cigarettes on cessation relative to NRT and control condition. Cochrane risk-of-bias tool for randomized trials Version 2 was used to access study bias.

Results

For the e-cigarette trials, our initial search identified 4,717 studies and we included 7 trials for NMA after removal of duplicates, record screening and assessment of eligibility (Total N = 5,674). For NRT trials, our initial search identified 1,014 studies and we included 9 trials that satisfied our inclusion criteria (Total N = 6,080). Results from NMA indicated that participants assigned to use nicotine e-cigarettes were more likely to remain abstinent from smoking than those in the control condition (pooled Risk Ratio (RR) = 2.08, 97.5% CI = [1.39, 3.15]) and those who were assigned to use NRT (pooled RR = 1.49, 97.5% CI = [1.04, 2.14]. There was a moderate heterogeneity between studies (I² = 42%). Most of the e-cigarette trials has moderate or high risk of bias.

Conclusion

Smokers assigned to use nicotine e-cigarettes were more likely to remain abstinent from smoking than those assigned to use licensed NRT, and both were more effective than usual care or placebo conditions. More high quality studies are required to ascertain the effect of e-cigarette on smoking cessation due to risk of bias in the included studies.

中文翻译：

---

电子烟戒烟随机对照试验和网络荟萃分析的系统评价

目的

电子烟或尼古丁电子烟产品是潜在的戒烟辅助工具，可为可燃香烟提供尼古丁和行为替代。本综述旨在通过使用网络荟萃分析（NMA），比较尼古丁电子烟与获得许可的尼古丁替代疗法（NRT）和基于无尼古丁的控制条件的戒烟效果。

方法

我们在 PubMed、Web of Science 和 PsycINFO 中检索了随机对照试验 (RCT)，这些试验分配个体使用尼古丁电子烟，并与使用经许可的 NRT（例如尼古丁贴片、尼古丁口香糖等）或不含尼古丁的电子烟的个体进行比较。控制病情，例如接受安慰剂（不含尼古丁）电子烟或常规护理。我们只纳入了对吸烟的健康个体的研究。此外，我们还确定了关于 NRT 的最新 Cochrane 综述，并检索了与我们确定的电子烟试验同期发表的 NRT 试验。NMA 旨在比较电子烟相对于 NRT 和对照条件对戒烟的影响。Cochrane 随机试验偏倚风险工具第 2 版用于评估研究偏倚。

结果

对于电子烟试验，我们最初检索了 4,717 项研究，并在删除重复项、记录筛选和资格评估后纳入了 7 项 NMA 试验（总 N = 5,674）。对于 NRT 试验，我们最初检索了 1,014 项研究，并纳入了 9 项满足纳入标准的试验（总 N = 6,080）。NMA 的结果表明，被分配使用尼古丁电子烟的参与者比对照组的参与者（合并风险比 (RR) = 2.08，97.5% CI = [1.39, 3.15]）和那些接受尼古丁电子烟的参与者更有可能保持戒烟。被分配使用 NRT（汇总 RR = 1.49，97.5% CI = [1.04, 2.14]。研究之间存在中等异质性 ( I ²  = 42%)。大多数电子烟试验具有中度或高度偏倚风险。

结论

被分配使用尼古丁电子烟的吸烟者比被分配使用许可的 NRT 的吸烟者更有可能保持戒烟，并且两者都比常规护理或安慰剂条件更有效。由于纳入的研究存在偏倚风险，需要更多高质量的研究来确定电子烟对戒烟的影响。