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Evidence summaries

Nicotine Replacement Therapy to Reduce Continued Tobacco Use

Nicotine replacement therapy with fast-acting products appears to be effective for smokers who want to reduce but not quit compared to placebo or reduction alone. It may also help quitting. Level of evidence: "B"

A Cochrane review [Abstract] 1 included 24 trials about interventions to help smokers cut down the amount smoked. Nicotine replacement therapy (NRT) significantly increased the odds of reducing cigarettes per day (CPD) by 50% or more for people using nicotine gum or inhaler or a choice of product compared to placebo (RR 1.75, 95% CI 1.44 to 2.13; 8 trials, n=3 081). Where average changes from baseline were compared for different measures, CO and cotinine consistently showed smaller reductions than CPD. Small numbers of smokers in either treatment or control group successfully sustained a reduction of 50% or more. Use of NRT increased the odds of quitting (RR 1.73, 95% CI 1.36 to 2.19).

A Cochrane review [Abstract] 2 assessed the effect of reduction-to-quit interventions on long-term smoking cessation. Reduction aided by pharmacotherapy resulted in higher quit rates compared to reduction alone (RR 1. 68, 95% CI 1.09 to 2.58; 11 studies, n=8636, I²=78%). However, a significant subgroup analysis suggested that this may only be true when fast-acting NRT or varenicline are used and not when nicotine patch, combination NRT or bupropion are used.

A meta-analysis 3 included 3 high-quality RCTs involving a total of 1607 subjects. The participants were adult smokers who were addicted to tobacco, defined as those who smoked at least 15 cigarettes or who had an end-expiratory carbon monoxide concentration of at least 15 ppm. Both groups used an equal amount of nicotine replacement therapy (NRT) before and after quitting smoking. The outcome measures were the prolonged and 7-day CO-verified abstinence rates. The prolonged abstinence rate of the gradual cessation group was significantly lower than that of the abrupt group (RR 0.77, 95% CI 0.68 to 0.98; I²=36%). The result of 7-day smoking cessation rate was also lower in the gradual group (RR 0.76 95% CI 0.61 to 0.94; I²=39%).

A retrospective, observational, cohort study 4 included 278 smokers with moderate-to-severe nicotine dependence who visited a Chinese smoking cessation outpatient clinic. Participants were divided into two groups by the cessation strategy: the abrupt cessation group (n=139, tobacco was not controlled during the first 3 weeks) and the gradual cessation group (n=139, tobacco was gradually reduced in the first 3 weeks). No significant difference in the 7-day point prevalence abstinence rates at 1, 3 and 6 months post-treatment was observed between the groups (p>0.05). The 1-month continuous abstinence rate of the gradual cessation group was higher than that of the abrupt cessation group (51.1% vs 31.7%; χ;2=10.812, p=0.001). The 3-month continuous abstinence rate of the gradual cessation group was also higher than that of the abrupt cessation group (42.4% vs 27.3%; χ;2=6.983, p=0.008).

Comment: The quality of evidence is downgraded by inconsistency (heterogeneity).

    References

    • Lindson-Hawley N, Hartmann-Boyce J, Fanshawe TR et al. Interventions to reduce harm from continued tobacco use. Cochrane Database Syst Rev 2016;(10):CD005231. [PubMed]
    • Lindson N, Klemperer E, Hong B et al. Smoking reduction interventions for smoking cessation. Cochrane Database Syst Rev 2019;(9):CD013183. [PubMed]
    • Tan J, Zhao L, Chen H. A meta-analysis of the effectiveness of gradual versus abrupt smoking cessation. Tob Induc Dis 2019;17():09 [PubMed]
    • Zhu N, Lin S, Dai L, et al. Abrupt versus gradual smoking cessation with pre-cessation varenicline therapy for Chinese treatment-seeking smokers: A retrospective, observational, cohort study. Tob Induc Dis 2022;20():29 [PubMed]

Primary/Secondary Keywords