Sigarette elettroniche per smettere di fumare: una revisione Cochrane

BACKGROUND: Electronic cigarettes (ECs) are portable electronic devices that produce an aerosol by heating an e-liquid. Smokers, healthcare professionals, and regulators need clarity on whether ECs can help people quit smoking and whether they are safe to use for this purpose.OBJECTIVES: To examine the safety, tolerability, and efficacy of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term abstinence from smoking compared with nicotine-free ECs, other smoking cessation treatments, or no treatment.SEARCH METHODS: The search was conducted by consulting the Cochrane Tobacco Addiction Group's Specialized Register as of 1 February 2023 and the Cochrane Central Register of Controlled Trials (Central), Medline, Embase, and PsycINFO databases as of 1 July 2023.SELECTION CRITERIA: Studies in which smokers were randomized to either EC or control groups, as well as uncontrolled intervention studies in which all participants received an EC intervention, were included, as these studies have the potential to provide further information on harms and their long-term use.DATA COLLECTION AND ANALYSIS: Standard Cochrane methods were used for data screening and extraction. Critical outcomes were smoking abstinence for at least six months, adverse events (AEs), and severe adverse events (SAEs). The Mantel-Haenszel fixed-effects model was used to calculate risk ratios (RRs) with 95% confidence intervals (CIs) for dichotomous outcomes. Mean differences were calculated for continuous outcomes. Where appropriate, data were pooled for pairwise and network meta-analysis analyses.RESULTS: Eighty-eight completed studies were included (ten new compared to the previous version of the review), representing 27,235 participants. Of these, 47 were randomized controlled trials (RCTs). Of the included studies, ten were classified as having a low risk of bias (all but one contributed to the main comparisons included in the review), 58 as having a high risk (including all non-randomized studies), and the remainder as having an unclear risk. There is high-quality evidence that nicotine-containing ECs increase cessation rates compared to nicotine replacement therapy (NRT). In absolute terms, this could translate into four additional cessation events per 100.There is moderate-quality evidence that the frequency of adverse events is similar between groups. SAEs were rare, and there is insufficient evidence to determine whether frequency rates differ between groups due to the high degree of data imprecision.There is moderate-quality evidence, again limited by imprecision, that ECs with nicotine increase cessation rates compared to ECs without nicotine. In absolute terms, this could lead to three additional cessation cases per 100 people. There is moderate-quality evidence that there is no difference in the rate of adverse events between these groups. There is insufficient evidence to determine whether SAE rates differ between groups due to very high imprecision in the data.There is also low-quality evidence (with a high risk of bias) suggesting that, compared to behavioral support only/no support, smoking cessation rates may be higher for EC users with nicotine. In absolute terms, this equates to four additional people quitting smoking per 100. Adverse events (non-serious) were more common in people using ECs with nicotine, while, again, the evidence was insufficient to determine whether the frequency of SAEs differed between groups.The results of the network meta-analysis were consistent with those of the pairwise meta-analyses for all critical outcomes, with no inconsistencies within the network. The adverse effects (short and medium-term), most commonly reported for nicotine-containing ECs, were throat or mouth irritation, headache, cough, and nausea. These appeared similar to those reported for NRT and tended to decrease over time.AUTHORS' CONCLUSIONS: There is high-quality evidence that ECs with nicotine increase smoking cessation rates compared to NRT and moderate-quality evidence that they increase cessation rates compared to ECs without nicotine. Evidence comparing ECs with nicotine to usual care/no treatment also suggests a positive effect of the former, but is related to risks of bias inherent in the study design. Confidence intervals were mostly wide for data on AEs, SAEs, and other safety indicators, notably with no differences in adverse events between ECs with and without nicotine, nor between ECs with nicotine and NRT.The overall incidence of SAEs was low. No serious harms were identified from the use of ECs with nicotine, but the lack of long-term data must be taken into account: the longest follow-up was two years, and the number of studies that included this evaluation was small.The main limitation of the available evidence remains imprecision due to the small number of randomized trials, often with low event rates. Further randomized trials are currently underway. To ensure the review continues to provide up-to-date information to decision makers, it has been structured as a living systematic review. Searches will be conducted monthly to provide rapid updates to the review whenever new, relevant evidence becomes available.