Perverse conclusion from results

John A. Stapleton, Senior Research Associate,
January 18, 2012

The results of the recent study by Alpert et al. were interpreted incorrectly with respect to the efficacy of nicotine replacement therapy (NRT).(1) The study only considered relative relapse rates among people who had already stopped smoking according to whether they had used NRT or not. This is clearly an inadequate design to address the issue of efficacy because it ignores the initial quit rates in the two groups. Only if the results had indicated significantly higher relapse among those using NRT might they have offered evidence against long-term NRT efficacy, depending, of course, on the initial difference in quit rates (not measured) and the difference in relapse rates. However, this was not the case. There was no evidence of differential relapse. Therefore, the conclusion that these data provide evidence against the effectiveness of NRT is wrong.

Had the authors considered more thoroughly the literature they would surely have been enlightened by the meta-analysis review of relapse and long-term NRT effectiveness published in Tobacco Control.(2) It would have helped them understand the issues and to draw an appropriate conclusion, rather than a perverse one. That review included 4792 randomized subjects (not self-selected as in the new study) followed up for several years and found the same result as Alpert: the relapse rate did not differ between those using NRT and others. Consequently, because the initial NRT quit rate was higher, efficacy remained after a mean follow-up time of 4.3 years (Odds ratio =1.99, 95% C.I. = 1.50 to 2.64). In contrast to the new study, all the subjects in that review received some form of professional support, although often minimal. Therefore, the same finding with respect to relapse in the new population-based study tends, if anything, to broaden rather than diminish the evidence for long-term NRT effectiveness.

(1) Alpert HR, Connolly GN, Biener L. A prospective study challenging the effectiveness of population-based medical intervention for smoking cessation. Tob Control 2012 10.1136/tobaccocontrol-2011-050129 Online 12 January

(2) Etter JF, Stapleton JA. Nicotine replacement therapy for long- term smoking cessation: a meta-analysis. Tob Control 2006;15(4):280-5.

Conflict of Interest:

John Stapleton has conducted trials of nicotine replacement and other treatments for tobacco dependence supported by the Medical Research Council, the Department of Health and Cancer Research UK. He was formally an adviser on issues of study design and methodology to several manufacturers of smoking cessation medications, including NRT, bupropion and varenicline.

Conflict of Interest

None declared