DOSE EFFECTS AND PREDICTORS OF OUTCOME IN A RANDOMIZED TRIAL OF TRANSDERMAL NICOTINE PATCHES IN GENERAL-PRACTICE

The transdermal nicotine patch has proved an effective aid to smoking cessation. The ease of securing good compliance gives it a potential a dvantage over nicotine gum as an adjunct to brief advice and support i n primary care settings where the major public health impact is obtain ed. In a preliminary report of half the sample of a randomized placebo controlled trial, we showed the patch to be effective in a general pr actice setting. We report here the definitive results of the full samp le, including dose effects, predictors of outcome and other issues of theoretical and practical interest. A total of 1200 heavy smokers (gre ater-than-or-equal-to 15 per day), attending 30 general practices in 1 5 English counties received brief GP advice, a booklet and 16 hours pe r day patch treatment for 18 weeks. Dose increase and abrupt vs. gradu al reduction of patch dosage were also randomized and follow-ups condu cted at 1, 3, 6, 12, 26 and 52 weeks. Outcome was measured by self-rep orted complete abstinence from week 3 to 52 with biochemical validatio n at all follow-up points. Nicotine patch treatment doubled the rate o f continuous abstinence up to 1 year (nicotine 9.6%, placebo 4.8%, p < 0.01); it most likely worked by reducing withdrawal symptoms. It enha nced cessation during the first week and reduced relapse during the se cond week. The dose increase after week 1 produced no sustained increa se in cessation. Gradual reduction was no better at preventing relapse than abrupt withdrawal of patches after week 12. Whether relapse woul d have increased by ending treatment at some point between weeks 3 and 12 was not tested. Although pre-treatment dependence on cigarettes wa s prognostic of failure, the patches were equally helpful to both high ly and less dependent smokers. Patches were particularly helpful to sm okers with pre-treatment subclinical dysthymic symptoms. All but one o f the 96 subjects eventually achieving long-term abstinence in the stu dy quit during the first week of cessation.