To accommodate and correct identifiable bias and risks of bias among clinical trials of nicotine replacement therapy (NRT).
Study Design and Setting
Meta-regression analysis of a published Cochrane Collaboration systematic review of 122 placebo-controlled clinical trials.
Both identified risks of bias and potential publication (or reporting or small sample) bias are associated with an increase in the reported effectiveness of NRT. Whenever multiple sources of biases are accommodated by meta-regression, no evidence of a practically notable or statistically significant overall increased rate of smoking cessation remains. Our findings are in stark contrast with the 50% to 70% increase in smoking cessation reported by the Cochrane Collaboration systematic review.
After more than 100 randomized clinical trials have been conducted, the overall effectiveness of NRT is in doubt. Simple, well-established meta-regression methods can test, accommodate, and correct multiple sources biases, often mentioned but dismissed by conventional systematic reviews.
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Published online: April 11, 2016
Accepted: March 9, 2016
© 2016 Elsevier Inc. All rights reserved.
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- Is nicotine replacement really ineffective? A reply to Stanley and MasseyJournal of Clinical EpidemiologyVol. 81
- PreviewDrs. Stanley and Massey  used a series of meta-regression analyses of the Cochrane Library review of nicotine replacement therapy (NRT) for smoking cessation [2,3] to estimate what the effectiveness of NRT would be if there were no publication, reporting, and small sample bias. They concluded NRT would not be effective. We believe this conclusion to be incorrect.
- New insights into smoking cessation question the effectiveness of nicotine replacement therapyJournal of Clinical EpidemiologyVol. 79
- PreviewStanley and Massey's  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 , the United Kingdom , and Australia  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% .