Examining e-cigarettes as a smoking cessation treatment: A critical umbrella review analysis

Introduction: This umbrella review identified the current high-quality systematic reviews on e-cigarettes as a smoking cessation aid. What is the comparative effectiveness of e-cigarettes compared to other cessation treatments or approaches? We also investigated the systematic reviews for reporting biases. Methods: This umbrella review was based on the Methods for Overviews of Reviews (MOoR) framework and the Preferred Reporting Items for Overviews of Reviews (PRIOR). The search was conducted in six databases and grey literature searches in four sources, plus four secondary searches. A Vote Counting Direction of Effect was selected for the analysis method because of high heterogeneity among the primary studies and the potential overweighting of data from two primary studies. Results: Sixteen systematic reviews were retrieved. Eight with an AMSTAR2 rating of moderate or high confidence were included, encompassing 24 randomized controlled trials. The analysis found that in 8 of 11 comparisons, e-cigarettes were more effective, and 3 of 11 comparisons reported no statistically significant difference. No reviews concluded that e-cigarettes were significantly less effective than any treatment or no treatment. Conclusions: Our analysis indicated that e-cigarettes are more effective than other treatments for smoking cessation. For ENDS compared solely to NRT, the evidence was mixed and still favored the effectiveness of ENDS. In any case, the success rates for cessation with ENDS was 10 %- 12 % at 6 months to one year, and the effect of relapse has not been sufficiently studied. New treatments and approaches are urgently needed. Registration: PROSPERO CRD42023406165; International Registered Report Identifier (IRRID): PRR1-10.2196/ 47711