Level 2: Mid-level evidence

Among smokers who are not attempting to quit, nicotine-replacement therapy aimed at reducing cigarette consumption may nevertheless increase cessation rates, based on a systematic Cochrane review (Cochrane Database Syst Rev. 2007[3]:CD005231).

Thirteen randomized or quasi-randomized trials evaluating interventions to reduce the amount smoked were included in the review. All but one trial had unclear concealment of allocation; one trial with adequate allocation concealment had differential losses to follow-up. Ten trials tested nicotine-replacement therapy to assist reduction; comparison was to placebo in eight trials.

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Comparing nicotine-replacement therapy vs. placebo, 12% vs. 6.4% had >50% reduction in cigarettes smoked per day or smoking cessation (P<.00001, NNT 18) in eight trials with 3,273 patients. Heterogeneity (P=.04) was explained by additional subgroup analyses: 25% vs. 21% had >50% reduction in cigarettes smoked per day or smoking cessation in two trials with 848 patients able to choose the type of nicotine-replacement therapy (P=.04, NNT 25); both these trials included patients who wanted to or were willing to reduce cigarette consumption. In four trials evaluating nicotine gum in 1,596 patients, the rates of smoking cessation were 6% vs. 1.6% (P=.00002, NNT 23); in two trials evaluating nicotine inhaler in 829 patients, the rates were 8.2% vs. 2.4% (P=.0005, NNT 18).

Nicotine-replacement therapy was associated with greater rates of smoking cessation at long-term follow-up at least six months from the start of the intervention (11% vs. 5.8%, P<.00001, NNT 20) in eight trials with 3,273 patients; results were similar in all three subgroups.Bupropion (Wellbutrin) was not significantly effective for smoking reduction or cessation in one trial.

Lifestyle consultation and motivational interviewing was associated with reduced cigarette consumption compared with untreated controls in one trial, but very few people who were offered the smoking-reduction group attended. Computerized scheduled reduction and reduction by selective elimination of cigarettes had similar results in one trial; both groups had significant reductions in cigarettes consumed from baseline, but there was no difference between groups.