Relapse prevention in UK Stop Smoking Services: current practice, systematic reviews of effectiveness and cost-effectiveness analysis.

BACKGROUND

Reducing smoking is a chief priority for governments and health systems like the UK National Health Service (NHS). The UK has implemented a comprehensive tobacco control strategy involving a combination of population tobacco control interventions combined with treatment for dependent smokers through a national network of NHS Stop Smoking Services (NHS SSS).

OBJECTIVES

To assess the effectiveness and cost-effectiveness of relapse prevention in NHS SSS. To (1) update current estimates of effectiveness on interventions for preventing relapse to smoking; (2) examine studies that provide findings that are generalisable to NHS SSS, and which test interventions that might be acceptable to introduce within the NHS; and (3) determine the cost-effectiveness of those relapse preventions interventions (RPIs) that could potentially be delivered by the NHS SSS.

DATA SOURCES

A systematic review of the literature and economic evaluation were carried out. In addition to searching the Cochrane Tobacco Addiction Group register of trials (2004 to July 2008), MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, PsycINFO, the Science Citation Index and Social Science Citation Index were also searched.

REVIEW METHODS

The project was divided into four distinct phases with different methodologies: qualitative research with a convenience sample of NHS SSS managers; a systematic review investigation the efficacy of RPIs; a cost-effectiveness analysis; and a further systematic review to derive the relapse curves for smokers receiving evidence-based treatment of the type delivered by the NHS SSS.

RESULTS

Qualitative research with 16 NHS SSS managers indicated that there was no shared understanding of what relapse prevention meant or of the kinds of interventions that should be used for this. The systematic review included 36 studies that randomised and delivered interventions to abstainers. 'Self-help' behavioural interventions delivered to abstainers who had achieved abstinence unaided were effective for preventing relapse to smoking at long-term follow-up [odds ratio (OR) 1.52, 95% confidence interval (CI) 1.15 to 2.01]. The following pharmacotherapies were also effective as RPIs after their successful use as cessation treatments: bupropion at long-term follow-up (pooled OR 1.49, 95% CI 1.10 to 2.01); nicotine replacement therapy (NRT) at medium- (pooled OR 1.56, 95% CI 1.16 to 2.11) and long-term follow-ups (pooled OR 1.33, 95% CI 1.08 to 1.63) and one trial of varenicline also indicated effectiveness. The health economic analysis found that RPIs are highly cost-effective. Compared with 'no intervention'; using bupropion resulted in an incremental quality-adjusted life-year (QALY) increase of 0.07, with a concurrent NHS cost saving of 68 pounds; for NRT, spending 12 pounds resulted in a 0.04 incremental QALY increase; varenicline resulted in a similar QALY increase as NRT, but at almost seven times the cost. Extensive sensitivity analyses demonstrated that cost-effectiveness ratios were more sensitive to variations in effectiveness than cost and that for bupropion and NRT, cost-effectiveness generally remained. Varenicline also demonstrated cost-effectiveness at a 'willingness-to-pay' threshold of 20,000 pounds per QALY, but exceeded this when inputted values for potential effectiveness were at the lower end of the range explored. For all drugs, there was substantial relapse to smoking after treatment courses had finished. Quit attempts involving NRT appeared to have the highest early relapse rates, when trial participants would be expected to still be on treatment, but for those involving bupropion and varenicline little relapse was apparent during this time.

LIMITATIONS

The qualitative research sample was small.

CONCLUSIONS

Based on the totality of evidence, RPIs are expected to be effective and cost-effective if incorporated into routine treatment within the NHS SSS. While staff within the NHS SSS were largely favourably inclined towards providing RPIs, guidance would be needed to encourage the adoption of the most effective RPIs, as would incentives that focused on the importance of sustaining quit attempts beyond the currently monitored 4-week targets.