Randomised trial of nicotine patches in general practice: results at one year
BMJ 1994; 308 doi: https://doi.org/10.1136/bmj.308.6942.1476 (Published 04 June 1994) Cite this as: BMJ 1994;308:1476
In the largest randomised, placebo controlled trial of nicotine patches in general practice we showed that the patch was effective in helping heavy smokers (>=15 cigarettes a day) to stop smoking in the short term.1 Among 1686 patients, rates of confirmed cessation three months after starting to use the patch were 19.4% with nicotine patches and 11.8% with placebo patches. These rates are similar to those reported by the only other randomised trial of a nicotine patch in British general practice.2
Trials of interventions to promote smoking cessation have shown that the effect of the intervention diminishes over time. Typically, about half of those abstinent at three months relapse by the end of a year.3 We report here the smoking cessation rates in our trial one year after the patients began to use the patch.
Subjects, methods, and results
Selection of subjects and methods has previously been reported.1 Briefly, 1686 patients, recruited from 19 general practices in Oxfordshire, were randomised into four equal groups: to receive a nicotine patch or a placebo patch in combination with a special booklet of support material or a standard Health Education Authority leaflet. Nicotinell TTS patches, in reducing sizes, were used over 12 weeks. Patients were reviewed by a trial nurse at one, four, eight, and 12 weeks.
At four or eight weeks, reported abstinence since the previous visit was confirmed by an exhaled carbon monoxide reading of <=10 ppm. At 12 weeks, reported abstinence since the previous visit was confirmed by a salivary continine concentration <=113.5 nmol/l (20 ng/ ml).4 For 36 patients who failed to provide a saliva sample, an exhaled carbon monoxide reading at 12 weeks of <=10 ppm counted as confirmatiom of non-smoking.
The 263 patients with confirmed cessation at 12 weeks were reviewed by the trial nurse at 24 and 52 weeks to ascertain their smoking status. Reported smoking cessation was confirmed by salivary cotinine concentration (165 of 180 confirmed at 24 weeks; 143 of 156 confirmed at 52 weeks) or exhaled carbon monoxide. Patients who failed to attend for review were assumed to be smokers.
Two outcome measures are reported: (i) continuous cessation from 12 weeks (confirmed at 12, 24, and 52 weeks) (ii) continuous cessation from one week (confirmed at 4, 8, 12, 24, and 52 weeks). The X2 test was used to compare proportions. Confidence intervals were calculated with the 1991 version of the BMJ's confidence interval analysis (CIA) program.
The significant advantage of the nicotine patch over the placebo patch, seen at the end of the treatment period, was still evident (though smaller) at one year (table). Of the 163 patients given nicotine patches who were abstinent at 12 weeks, 91 (56%) maintained abstinence to 52 weeks; 76/91 (84%) were abstinent continuously from the first week.
Numbers (percentages) of patients confirmed to have stopped smoking
Sustained cessation rates did not differ between patients who received the special support booklet and those who received the standard leaflet: continuous cessation from 12-52 weeks was confirmed in 78/842 (9.3%) and 78/844 (9.2%), and from 1-52 weeks in 63/842 (7.5%) and 66/844 (7.8%) respectively.
Comment
The relapse rate after use of nicotine patches in general practice is similar to that in other settings. In this trial and in the two other published randomised trials in general practice, about half the patients abstinent at the end of three months' treatment remained abstinent at one year.2,5
With strict validation criteria, our sustained cessation rate was 10.8%, a clinically useful result in a group of heavy (average 24 cigarettes/day) and long standing (average 25 years) smokers.
A striking result was the high sustained cessation rate in the placebo group. It is not possible to isolate the factors contributing to this effect, but in in addition to the placebo patch the scheduled follow up by a nurse is likely to have been important. Four factors seem to contribute to success in smoking cessation in primary care: selection of motivated patients, initial advice from doctors, follow up support by nurses, and nicotine replacement. The efficacy of nicotine patches obtained over the counter and used without support remains uncertain.
This study was supported by Ciba Pharmaceuticals; we thank them for important contributions to this study. We also thank Professor Nicholas Wald for continine measurements.
Coordinating general practitioners in the practices were Peter Burke, Andrew Chivers, John Clements, Martin Dawes, Ian Eastwood, David Ebbs, Rickman Godlee, Richard Harrington, Karen Kealey, Neil MacLennan, David Mant, Janet Murray, Mary Nichols, Helen van Oss, David Stern, Richard Stevens, David Thurston, Robin Wilson, and Stephen Wood. Study nurses were Katrina Agnew, Mardy Bartlett, Jennifer Hodgeman, Karen Lindsey, and Jo Tissier. Research staff were Wendy Dobbie, Godfrey Fowler, Alice Fuller, Lesley Jones, David Mant, Margaret Thorogood, and Pat Yudkin. The report was prepared by Pat Yudkin, Lesley Jones, and Godfrey Fowler.