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Systematic Review
This review aims to address questions of clinical effectiveness for NRT, bupropion, and varenicline in the general population of tobacco users. 1. What is the comparative clinical effectiveness of nicotine replacement therapy versus bupropion or varenicline in the general population of tobacco users? 2. What is the comparative clinical effectiveness of nicotine replacement therapy, bupropion or varenicline versus placebo in the general population of tobacco users?
Ten relevant studies are included in this review. The clinical effectiveness of nicotine replacement therapy (NRT) compared to bupropion was found to be similar. Studies that compared varenicline to NRT reported higher rates for abstinence for participants in the varenicline group. There is some evidence to suggest that participants using bupropion, and those using varenicline achieved higher rates of abstinence when compared to placebo. Findings for NRT versus placebo or control were mixed, with some studies reporting no difference and one study reporting higher rates of abstinence for those on NRT.
The findings of this report should be considered in the context of the previous CADTH HTA on the subject, which employed a more thorough methodology and analysis of the primary studies on this topic.1 The HTA found that varenicline was superior to bupropion and conventional use of the nicotine patch, and that all pharmacotherapies included in the HTA were efficacious in aiding the general population to quit smoking.1 The current review gives an overview of the recent evidence published since this HTA, and provides areas for consideration within the body of evidence on this subject, including the previous CADTH HTA. Regarding NRT versus placebo, most studies published between 2012 and 2016 showed no difference in tobacco related outcomes, but the research was conducted in specific sub-populations (e.g., adolescents, smokeless tobacco users, or persons who had previously quit and were preventing relapse) and may be less relevant to the general population of smokers. The findings and recommendations of the HTA are still considered relevant.
Ten relevant studies are included in this review. The findings suggest that varenicline groups achieved higher rates of abstinence compared to both NRT and placebo, bupropion and NRT were of similar effectiveness, and bupropion and varenicline both had higher abstinence rates compared to placebo. The number of SRs that reported adverse events in any of the treatment groups was six. When side effects did occur, they were usually mild in presentation and localized (e.g., skin irritation from the nicotine patch). It is uncertain how much these findings of clinical effectiveness were influenced by the baseline characteristics of the study participants (e.g., how many cigarettes they smoked per day prior to therapy), as well as the differences among the behavioural therapies being offered along with the pharmacological therapies. These behavioural interventions differed across the studies, as therapies counselling and information presented as a booklet. Many smoking and tobacco cessation programs offer a combination of behavioural and pharmacological interventions.1 The success of these cessation programs may depend on the type of treatment being offered.