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The clinical significance and assessment of smoking cessation treatments

This article discusses the importance and assessment of smoking cessation treatments, highlighting the impact on life expectancy, cost-effectiveness, need for rigorous evaluation, and the effectiveness of existing interventions. It also explores the efficacy of different support methods and medications, such as face-to-face individual support, group support, telephone counseling, tailored internet support, and medication options.

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The clinical significance and assessment of smoking cessation treatments

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  1. The clinical significance and assessment of smoking cessation treatments Robert West University College London London March 2008

  2. The importance of each quit attempt • After the age of 40, each year that stopping is delayed loses an average of 3 months of life (Doll et al 2004) • It is likely to be an average of at least a year before the next quit serious attempt • Therefore, failing at the current quit attempt probably loses an average of 3 months of life • Therefore each serious quit attempt is a precious resource that should be given the maximum possible chance of success • Increasing that chance by even a small amount is clinically meaningful

  3. Cost-effectiveness • Treatments that aid cessation have the potential to be extremely cost effective in saving lives • Even those that increase long-term success of an attempt by 1% (e.g. from 5% to 6%) represent cost-effective clinical interventions at a cost of 150 euros per smoker (West, 2007)

  4. The need for rigorous assessment • It is essential to evaluate treatments using the most rigorous possible methods: • To know whether the typically small effects found are reliable • To avoid the financial and opportunity cost of failed quit attempts using ineffective methods • To enable smokers to distinguish between genuinely helpful treatments and ones that are promoted by commercial companies selling ‘snake oil’

  5. Assessment of ‘efficacy’ • This normally involves: • Using continuous abstinence for at least 6 months from an appropriate point after the quit date as the primary outcome measure • Intention to treat analysis with those lost to follow-up counted as continuing smokers • Biochemical verification of claims of abstinence • Assessment of smoking status blind to experimental condition • These and other criteria are embodied in the ‘Russell Standard’ (West et al, 2005)

  6. Assessment of effectiveness • Efficacy does not necessarily translate into ‘effectiveness’ in routine clinical practice • Need to examine quit rates in routine clinical practice and in population studies • Compare quit rates in prospective studies in those using and not using treatments adjusting for prognostic indicators

  7. Effectiveness of existing interventions • Professional behavioural support, nicotine replacement therapies, bupropion, nortriptyline and varenicline all have proven effectiveness and can help 4% to 16% of users to achieve 6 months of continuous abstinence in a given quit attempt; this translates into 2% to 8% permanent cessation

  8. Face-to-face individual support: Efficacy Using only studies with ≥6 months’ continuous abstinence and biochemical verification

  9. Group support: efficacy Using only studies with ≥6 months’ continuous abstinence and biochemical verification

  10. Effect of telephone counselling Cochrane review: ≥6 month cessation not biochemically validated

  11. Effect of tailored internet support Not biochemically verified

  12. Effect of NRT Cochrane: LI: Low intensity behavioural support; HI: High intensity behavioural support RTS: Reduce To Stop; Combination: various combinations versus single NRT types; Population: NRT versus no NRT in population samples without behavioural support (ATTEMPT – cohort study, not RCT)

  13. Effect of nortriptyline, bupropion and varenicline For bupropion and nortriptyline data from Cochrane: ≥6 months’ continuous abstinence and biochemical verification; varenicline 6 month continuous abstinence data from JAMA 2006; blue shading shows effect on 12 month continuous abstinence rates of further 12w varenicline vs placebo in smokers abstinence at 12w

  14. Face-to-face individual support plus medication: effectiveness • Evaluation of the NHS stop smoking services: • 12-month continuous abstinence rates of 15% accords with what would be expected from trials • Specialist support in groups more effective than individual support • NHS stop smoking services with varenicline 60% 4-week success rates versus 50% with NRT and bupropion • Pragmatic trial of individual support in primary care failed to find effect (Aveyard et al, 2007)

  15. Conclusions • Clinical interventions to aid smoking cessation can be very cost effective ways of preventing premature death even when the effect sizes are small • It is very important to apply rigorous evaluation to these methods to get the best estimates of efficacy and effectiveness • This usually involves at least 6-month follow-up, intention to treat analysis and biochemical verification • Gold standard treatment is multi-session behavioural support provided by specialist plus medication – probably varenicline or optimal use of NRT • Telephone support and internet-based support also look to be effective

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