Source: Stead LF, Perera R, Bullen C,Mant D, Hartmann-Boyce J, Cahill K, Lancaster T. Nicotine replacement therapy for smoking cessation. Cochrane Database of Systematic Reviews 2012, Issue 11. Art. No.: CD000146.
Efficacy Endpoints: Abstinence from smoking at ≥ six months
Harm Endpoints: Chest pain/palpitations, Cardiovascular events
Narrative: Smoking kills more than five million individuals worldwide and about 443,000 individuals Americans each year. Cigarette and tobacco use cost the United States $193 billion a year in healthcare related expenditures1.
Recent data suggest that up to 70% of current smokers want to quit2. Cessation has been shown to lower risks of lung and other smoking-attributable cancers, coronary artery disease, stroke, peripheral vascular disease, chronic obstructive pulmonary disease, and infertility, while improving lung function and symptoms3. Yet, despite known health effects, stigma, and costs, 19% of Americans (44 million) still smoke4.
Nicotine dependence, the most common form of chemical addiction, may be comparable to that of heroin, cocaine, or alcohol (American Society of Addiction Medicine, 2010). Nicotine Replacement Therapy (NRT) has been suggested as a plausible method to help people quit smoking. NRT is available in a variety of forms, including gums, patches, tablets, inhalers, and sprays.
This review includes 150 studies enrolling over 50,000 subjects comparing NRT to placebo. Overall, NRT increased successful cessation rates from 10 to 17%, with a number needed to treat (NNT) of 15.
The relative benefit of NRT on smoking cessation was independent of delivery method, definition of abstinence, length of treatment, level of support counseling, treatment venue (hospital, clinic, support group) and whether a fixed, variable, or tapered dose was used. Success rates were even higher when NRT was simply available over the counter.
The use of NRT slightly increased rates of symptomatic chest pains and palpitations (OR 1.88, NNH 94), similar to an earlier study5. Other fairly-rare side effects varied with type of NRT and included GI upset, dental problems, and jaw pain (gum); skin irritation (patch); throat/nose irritation, sore throat (inhaler, lozenge, spray); and headache, dizziness, sleep disturbance, hiccups (general).
Importantly, this review, in line with previous studies6 ,7,8 has found that NRT is not associated with any significant increase in cardiovascular events and is safe to use during pregnancy.
Caveats: This review included thousands of patients in a large number of high-quality, randomized controlled trials. Most studies were supported by public funds and grants, although a large number received NRT products, and a smaller number, direct funding from pharmaceutical companies, which may falsely augment the treatment effect size9.
Most trials included only heavy smokers (≥ 15 cigarettes per day); the average number of cigarettes smoked was ~20. Therefore, it is unclear how this study may apply to lighter smokers. Pregnant women also demonstrated less benefit than other populations.
In general, the authors attempted to produce a conservative estimate, by assuming all patients lost to follow up were treatment failures and by contacting other researchers for unpublished data to limit publication bias. Additionally, only complete quitting and not smoking reduction was assessed10.
The control unassisted or self-quit rate in this study (~10%) was higher than others published (3-5%11). Applying the same relative benefit of NRT to a baseline quit rate of 3-5% would yield an absolute risk reduction (ARR) of ~2% with a NNT of ~50. If the baseline rate was 15%, the ARR would be 8% with a NNT of 11. Thus, although NRT’s relative benefit appeared consistent, the absolute effect may vary with other factors (behavioral support, financial incentives, etc).
Similarly, although the benefit of NRT continued to hold at 12 months, the absolute rates of abstinence declined. A separate meta-analysis extends this follow up beyond one year12.
Given the quality of research and the lack of serious adverse effects, NRT appears to be a safe and effective option for current smokers who wish to quit.
Author: Gary Green, MD
Published/Updated: May 1, 2013
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