Abstract
BACKGROUND: An increasing number of randomized controlled trials (RCTs) investigated various forms of acupuncture for smoking cessation; however, their findings remain inconsistent, and substantial controversy persists regarding both its efficacy and safety. OBJECTIVES: This overview aimed to synthesize the outcome evidence presented in existing systematic reviews (SRs) on acupuncture for smoking cessation, appraise the methodological quality of the included SRs, and re-evaluate the primary outcomes. METHODS: A comprehensive literature search was conducted in eight databases from inception to December 31, 2024, with no language restrictions. Two independent reviewers screened the eligible studies. The methodological quality of the included SRs was assessed using A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2). The Risk of Bias in Systematic Reviews (ROBIS) tool was used to evaluate potential bias. Reporting quality was assessed with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 checklist. The certainty of evidence from the SRs was rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. After removing duplicate randomized controlled trials, we re-conducted meta-analysis for the primary outcomes using R software version 4.4.2 and TSA Viewer version 0.9.5.10, and performed trial sequential analysis (TSA) to examine the reliability and robustness of the findings. RESULTS: This overview included 10 SRs, covering 74 RCTs. Using AMSTAR 2, ROBIS, and PRISMA 2020 for evaluation, we found that the methodological quality, risk of bias, and reporting quality of the 10 SRs were unsatisfactory. The quality of evidence evaluated by GRADE was mostly rated as low or critically low; however, acupuncture appeared to contribute to improved abstinence rates. In the updated meta-analysis, acupuncture showed superiority over sham acupuncture for short-term abstinence (RR = 1.37, 95% CI: 1.08, 1.73, p = 0.0092) and outperformed waiting list controls (p = 0.0204). However, no significant benefits were observed for long-term abstinence compared to sham, nor was acupuncture superior to nicotine replacement therapy or behavioral therapy. Furthermore, TSA indicated that the required information size was not reached, suggesting a risk of false-positive findings for the short-term benefit. CONCLUSION: Although the evidence for acupuncture in smoking cessation remains insufficient, acupuncture appears to improve short-term abstinence rates. However, substantial heterogeneity and methodological limitations were identified. TSA suggested a potential risk of false-positive findings, highlighting the need for further high-quality research. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD42023473514, identifier CRD42023473514.