Effectiveness of smoking cessation therapies: A systematic review and meta-analysis

Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada. <>
BMC Public Health (Impact Factor: 2.26). 12/2006; 6(1):300. DOI: 10.1186/1471-2458-6-300
Source: PubMed


Smoking remains the leading preventable cause of premature deaths. Several pharmacological interventions now exist to aid smokers in cessation. These include Nicotine Replacement Therapy [NRT], bupropion, and varenicline. We aimed to assess their relative efficacy in smoking cessation by conducting a systematic review and meta-analysis.
We searched 10 electronic medical databases (inception to Sept. 2006) and bibliographies of published reviews. We selected randomized controlled trials [RCTs] evaluating interventions for smoking cessation at 1 year, through chemical confirmation. Our primary endpoint was smoking cessation at 1 year. Secondary endpoints included short-term smoking cessation (approximately 3 months) and adverse events. We conducted random-effects meta-analysis and meta-regression. We compared treatment effects across interventions using head-to-head trials and when these did not exist, we calculated indirect comparisons.
We identified 70 trials of NRT versus control at 1 year, Odds Ratio [OR] 1.71, 95% Confidence Interval [CI], 1.55-1.88, P =< 0.0001). This was consistent when examining all placebo-controlled trials (49 RCTs, OR 1.78, 95% CI, 1.60-1.99), NRT gum (OR 1.60, 95% CI, 1.37-1.86) or patch (OR 1.63, 95% CI, 1.41-1.89). NRT also reduced smoking at 3 months (OR 1.98, 95% CI, 1.77-2.21). Bupropion trials were superior to controls at 1 year (12 RCTs, OR1.56, 95% CI, 1.10-2.21, P = 0.01) and at 3 months (OR 2.13, 95% CI, 1.72-2.64). Two RCTs evaluated the superiority of bupropion versus NRT at 1 year (OR 1.14, 95% CI, 0.20-6.42). Varenicline was superior to placebo at 1 year (4 RCTs, OR 2.96, 95% CI, 2.12-4.12, P =< 0.0001) and also at approximately 3 months (OR 3.75, 95% CI, 2.65-5.30). Three RCTs evaluated the effectiveness of varenicline versus bupropion at 1 year (OR 1.58, 95% CI, 1.22-2.05) and at approximately 3 months (OR 1.61, 95% CI, 1.16-2.21). Using indirect comparisons, varenicline was superior to NRT when compared to placebo controls (OR 1.66, 95% CI 1.17-2.36, P = 0.004) or to all controls at 1 year (OR 1.73, 95% CI 1.22-2.45, P = 0.001). This was also the case for 3-month data. Adverse events were not systematically different across studies.
NRT, bupropion and varenicline all provide therapeutic effects in assisting with smoking cessation. Direct and indirect comparisons identify a hierarchy of effectiveness.

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    • "Smoking accounts for more deaths and diseases worldwide than any other modifiable risk factors[1,2]. Literature suggests that approximately three quarters of smokers want to quit; however, smoking is highly addictive and smoking cessation is difficult with frequent relapses common amongst those who try to quit[1]. There is ongoing research on the effectiveness of various smoking cessation interventions. "

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    • "In addition, the antihypertensive medication clonidine and the tricyclic antidepressant nortriptyline are sometimes used as second-line agents for smoking cessation, but their use is not FDA approved for this indication [7]. The most widely used product in Europe and the United States is NRT, which increases smoking cessation rates at one year by approximately 70% [6,8]. Clinical trials have demonstrated statistically significant improvement in smoking cessation with varenicline and bupropion [9,10]. "
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    ABSTRACT: Pharmacologic therapies have an important role in the success of interventions for smoking cessation. This study aims to determine the efficacy of several pharmacologic treatments in patients who applied to a smoking cessation clinic. This retrospective study includes 422 patients who presented to our smoking cessation clinic between January 2010 and June 2013, used the pharmacologic treatment as prescribed and completed the one-year follow-up period. All patients were assessed using the Fagerström Test for Nicotine Dependence (FTND) and received both behavioral therapy and pharmacotherapy. Patients' smoking status at one year was assessed by telephone interview. The patients were 24.3% female (103/422) and 75.7% male (319/422) with a mean age of 38 ± 10 years. Patients were divided into three groups: varenicline (166 patients), bupropion (148 patients) and nicotine replacement therapy (108 patients).The smoking cessation rates of these groups were 32.5%, 23% and 52.8%, respectively, and were statistically significant (p > 0.001). The overall success rate was 35%. Further analysis revealed that pharmacologic therapy (p > 0.001) and gender (p = 0.01) were factors that showed statistically significant effects on smoking cessation rates. Males had higher success rates than females. The overall relapse rate was 21.6% and the bupropion group showed the highest relapse rate among treatment groups. Lack of determination emerged as the most important factor leading to relapse. Nicotine replacement therapy was found to be more effective at promoting abstinence from smoking than other pharmacologic therapies.
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    • "The effectiveness booklet failed to create a significant increase in 4-week smoking cessation levels. Successful quitting is influenced by a number of additional processes happening within the smoking cessation attempt other than attendance, such as severity of withdrawal symptoms (Piper, Schlam, Cook, Sheffer, Smith & Loh et al., 2011), life events (Kriegbaum, Larsen, Christensen, Lund & Osler, 2011), and choice of cessation medication (Wu et al., 2006). We detected an odds ratio for 4-week quit status of 1.55, and although non-significant, replication with a larger sample size may narrow the confidence intervals and demonstrate a significance impact. "
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    ABSTRACT: Objectives The National Health Service (NHS) Stop Smoking Service (SSS) is an extremely cost-effective method of enabling smoking cessation. However, the SSS is only used by a minority of smokers. Developing interventions to maintain service attendance may help to increase the number of quitters. This study pilots an intervention aimed at maintaining attendance by (1) increasing motivation to attend through a booklet providing evidence of service effectiveness and (2) strengthening the link between motivation to attend and attendance through forming an implementation intention. DesignA factorial randomized controlled trial. MethodsA total of 160 newly enrolled smokers at the Surrey NHS SSS were recruited and randomly assigned to one of four conditions: (1) standard care (SC), (2) SC+effectiveness booklet, (3) SC+implementation intention, and (4) SC+effectiveness booklet+implementation intention. The outcome measures included attendance at the SSS and the 4-week quit rate. ResultsThe booklet increased service attendance (OR=2.93, p<.01, 95% CI=1.45-5.93; Number Needed to Treat=3.3) but had no impact on the 4-week quit rate (OR=1.55, 95% CI=0.75-3.21). Forming an implementation intention had no impact on service attendance or the 4-week quit rate. Attending the service was associated with a higher 4-week quit rate (=87.52, p<.001). Conclusions Presenting information about the effectiveness of the service improved service attendance. A larger trial now needs to evaluate whether this intervention can also increase the quit rate.
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