Stanley and Massey's [
[1]
] recent analysis of a Cochrane systematic review on smoking cessation is an important addition to the ongoing debate around the efficacy of nicotine replacement therapy (NRT) and other pharmaceutical interventions in helping smokers to quit. Proponents of NRT, including leading clinical and professional bodies in the United States [[2]
], the United Kingdom [[3]
], and Australia [[4]
] base their position on randomized clinical trials (RCTs) which typically report that the use of pharmacotherapy increases cessation success rates, compared to placebo or no assistance, by as much as 50–70% [[5]
].Such confidence in NRT, however, has come under scrutiny. The reality is that most ex-smokers have quit without assistance [
[6]
]. This discrepancy is explained by the fact that results returned by RCTs are not replicated at a population level because trial conditions are far removed from the “real-world” settings in which smokers attempt to quit [[4]
]. In addition, much of the research apparently demonstrating impressive results for cessation using NRT (including studies analyzed in Cochrane systematic reviews) has been funded by pharmaceutical corporations that produce cessation products, raising concerns about conflicts of interest [4
, 7
]. Despite this, Cochrane reviews remain a key source of evidence cited by NRT proponents [[8]
].The significance of Stanley and Massey's study is that it moves beyond the current discourse around trial vs. “real-world” results and related concerns about industry funding of research, to a consideration of the validity of the findings of Cochrane reviews. Their meta-regression analysis of more than 100 clinical trials [
[5]
] incorporated tests for sources of bias generally not included in systematic reviews. Once these sources of bias are taken into account, they found no statistical evidence that NRT is effective in helping smokers to quit; this finding differs significantly from the 50% to 70% increase in smoking cessation for NRT over placebo reported in the Cochrane review [[5]
]. Furthermore, Stanley and Massey's study is important evidence indicating that the value of NRT as an effective means of smoking cessation has been overstated and that clinical bodies recommending its use should reconsider their advice to medical and health care workers and the public.References
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- Potential conflict of interest and bias in the RACGP's smoking cessation guidelines: are GPs provided with the best advice on smoking cessation for their patients?.Public Health Ethics. 2015; 8: 319-331
- Nicotine replacement therapy for smoking cessation (Review).Cochrane Database Syst Rev. 2012; : CD000146
- Prevalence of unassisted quit attempts in population-based studies: a systematic review of the literature.Addict Behav. 2014; 39: 512-519
- The global research neglect of unassisted smoking cessation: causes and consequences.PLoS Med. 2010; 7: e1000216
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Article info
Publication history
Published online: June 29, 2016
Footnotes
Funding: R.M. received funding from The National Institutes of Health (grant no. R01 CA091021-10A1), and W.R. received funding from the Australian Research Council via DP120101012.
Conflict of interest: None.
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© 2016 Elsevier Inc. All rights reserved.
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- Evidence of nicotine replacement's effectiveness dissolves when meta-regression accommodates multiple sources of biasJournal of Clinical EpidemiologyVol. 79
