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 randomised 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 analysed 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 versus ‘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]. Further, 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.
Acknowledgments
Funding Statement
Ross MacKenzie received funding from The National Institutes of Health [Grant No. R01 CA091021-10A1], and Wendy Rogers received funding from the Australian Research Council via DP120101012.
Footnotes
Conflict of Interests Declaration
No conflicts of interest to declare.
Contributor Information
Ross MacKenzie, Email: ross.mackenzie@mq.edu.au, Department of Psychology, Faculty of Human Sciences, Macquarie University, Sydney, New South Wales, Australia 2109, (02) 9850 56593.
Wendy Rogers, Email: wendy.rogers@mq.edu.au, Department of Philosophy and Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia.
References
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