Authors' objectives:

"The primary objective of this assessment report was to examine the effectiveness and cost-effectiveness of Nicotine replacement therapy (NRT) for 'cut down to stop' or 'cut down to quit'(CDTQ) smoking." (from executive summary)

Authors' results and conclusions: No systematic reviews of the effectiveness of CDTQ were identified. No RCTs specifically addressing CDTQ were identified. Seven randomised placebo-controlled trials satisfied the inclusion criteria; six of these were industry sponsored. The RCTs were primarily designed to investigate the effectiveness of a smoking reduction programme. Sustained smoking cessation was only reported as a secondary outcome in these trials and required commencement of cessation within the first 6 weeks of treatment. In four RCTs smokers received NRT gum or placebo, in two NRT inhalator or placebo and in one placebo-controlled RCT smokers exercised free choice of the type of NRT they received. Meta-analyses of the study level results for sustained abstinence from smoking, point prevalence of smoking abstinence, sustained smoking reduction and point prevalence of smoking reduction demonstrated statistically significant superiority of NRT compared with placebo for all four outcomes. The proportion of participants who achieved sustained abstinence commencing within the first 6 weeks of treatment was meagre (about 2% of those in receipt of NRT). This is not surprising given that it is inherently unlikely that smokers who had expressed unwillingness or inability to quit in the short term would stop within 6 weeks. Therefore, individual patient data from unpublished reports of five RCTs were used to calculate sustained abstinence of at least 6 months starting at any time during the treatment period (generally 12 months). Using this more realistic criterion for sustained abstinence, meta-analysis indicated statistically significant superiority of NRT versus placebo [relative risk 2.06, 95% confidence interval (CI) 1.34 to 3.15]. The proportions achieving this outcome across all five RCTs were 6.75% (95% CI 5.3 to 8.56%) of participants in receipt of NRT and 3.29% (95% CI 2.56 to 4.21%) of those receiving placebo. The number-needed-to-treat was 29. This measure of sustained abstinence was used for economic modelling. No significant treatment-related adverse events were reported in the trials and minor events were similar in frequency and type to those in previously reported studies of NRT. None of the included studies reported health-related quality of life measures for abstainers from smoking.

Authors' recommendations: Meta-analysis of RCT evidence of quit rates in NRT-supported smoking reduction studies indicates that NRT is an effective intervention in achieving sustained smoking abstinence for smokers who declare unwillingness or inability to attempt an abrupt quit. The 12-month sustained abstinence success rate in this population (approximately 5.3% with NRT versus approximately 2.6% with placebo) is considerably less than that documented for an abrupt quit NRT regime in smokers willing to attempt an abrupt quit with NRT (which according to other systematic reviews is approximately 16% with NRT versus 10% with placebo). Most of the evidence of effectiveness of CDTQ in this report came from trials that required considerable patient;investigator contact. Therefore, for CDTQ with NRT to generate similar abstinence rates for this recalcitrant population in a real-world setting would probably require a similar mode of delivery. Decision analytic modelling based on reasonable assumptions about costs, benefits and success rates suggests that CDTQ is highly cost-effective compared with no quit attempt. CDTQ remains cost-effective if dilution from abrupt quitting forms a small proportion of CDTQ attempts. In an alternative analysis in which smokers who switch from an abrupt quit to CDTQ retain the success rate of abrupt quitters, all forms of CDTQ appear cost-effective. Recommendations for further research Randomised trials in recalcitrant smokers allowing head-to-head comparison of CDTQ delivered with various NRT modalities (e.g. inhalator, nasal spray, lozenge, gum, patch) would be informative. Research is also needed into the best ways of implementing a CDTQ strategy and integrating this with abrupt quit options in the context of all UK smoking services.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.hta.ac.uk/1542

Year Published: 2008

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

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