Summary of findings: e-cigarettes versus nicotine replacement therapy (NRT) for nicotine abstinence, allocated product use and smoking cessation
| Outcomes | Relative effect (risk ratio (95% CI)) | Number of participants (studies) | Certainty of the evidence (GRADE) | Comments |
| Nicotine abstinence | 0.50 (95% CI 0.32–0.77) | 1568 (three RCTs) | Moderate | Downgraded one level due to imprecision (i.e. overall, a small number of events) |
| Allocated product use among successful tobacco quitters at the end of the trial | 8.94 (95% CI 3.98–20.07) | 180 (three RCTs) | Low | Downgraded two levels due to imprecision (i.e. overall, a small number of events and too wide confidence intervals) |
| Smoking cessation | 1.58 (95% CI 1.20–2.08) | 1598 (four RCTs) | Moderate | Downgraded one level due to imprecision (i.e. overall, a small number of events) |
Patient or population: adult current smokers; setting: Australia, New Zealand, UK and USA; intervention: e-cigarettes; comparison: NRT. GRADE: Grading of Recommendations Assessment, Development and Evaluation; RCT: randomised controlled trial. GRADE Working Group grades of evidence [10]: high – the authors have a lot of confidence that the true effect is similar to the estimated effect; moderate – the true effect is probably close to the estimated effect; low – the true effect might be markedly different from the estimated effect; very low – the true effect is probably markedly different from the estimated effect.