Long-Term Effectiveness of Tobacco Smoking Cessation Interventions in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Background: Smoking is a major global health problem. It kills more than half of the users. At least 1.18 billion people smoked cigarettes every day as of 2020. Although many interventions for tobacco smoking cessation have been implemented, their effectiveness remains unclear. This study aimed to assess the long-term effectiveness of various smoking cessation interventions in adults.

Design: We conducted a systematic review and meta-analysis of randomized controlled trials reporting long-term outcomes.

Methods: Evidence searches were conducted in the Cochrane Library, Embase, Medline-OVID, PubMed, Web of Science, and Clinicaltrials.gov. Two researchers searched until August 2023 without restrictions on country, language, or year of publication. The risk ratio (RR) for continuous abstinence was obtained through biochemical verification at measurements ≥ 6 months post-intervention. Data were extracted and assessed for quality using Risk of Bias 2. Meta-analysis was carried out using a random effects model. Subgroup analyses and meta-regression were performed to explore moderator variables. Sensitivity and publication bias analyses were also performed.

Results: Twenty-two effect sizes from 13 studies showed that tobacco smoking cessation interventions increased continuous abstinence by 2.5 times (RR 3.52; 95% CI; 2.19-5.65). The highest ratio was in the behavioral intervention (RR 7.83) with more than 6 months of therapy (RR 10.57). The tobacco smoking cessation intervention worked better in 55-64 years (RR 7.29), especially in Asia (RR 10.08). The intervention was more effective for female respondents (RR 4.21) and combination therapy format (RR 3.82). However, meta-regression showed that differences in gender and therapy format did not significantly influence the effectiveness of tobacco smoking cessation interventions in adults (p values 0.2748 and 0.8769). Sensitivity analysis (p-value 0.0025) further strengthens the evidence of the conclusions and credibility of the findings.

Conclusion: Behavioral therapy lasting more than 6 months was the most successful tobacco smoking cessation intervention in respondents aged 55-64 years, especially when implemented in Asia. Although not significant, therapies delivered in combination formats, especially in women, have the potential to increase continuous abstinence for adults. These findings provide important evidence for developing effective prevention and treatment strategies for long-term smoking cessation concerning the type, format, and total of therapy.

Keywords: adult smokers; behavioral therapy; biochemical verification; continuous abstinence; long‐term effectiveness; meta‐analysis; systematic review.