Background: Several placebo-controlled randomized trials have shown a substantial effect of many products used for smoking cessation. The trials have revealed results by performing either a direct or indirect comparisons. The present metaanalysis is an endeavor to compare the effect of the currently available and widely used seven pharmacological interventions as an aid to smoking cessation.
Methods: The databases like MEDLINE, EMBASE and the Cochrane reviewed published trials were investigated and further screened to meet the inclusion criteria. For example, only double-blind randomized controlled trials were included who have validated the results of abstinence at 6 and 12 months biochemically.
Results: A total of 69 trials were identified with a total number of 32,908 participants. Out of seven therapies chosen for the analysis, six were found to be more effective than placebo, the odds ratio (OR) for varenicline was 2.41, 95% CI 1.91–3.12, for nicotine spray (OR) 2.37, 95% CI 1.12–5.13, bupropion with (OR) 2.07, 95% CI 1.73–2.55, transdermal nicotine patch (OR) 2.07, 95% CI 1.69–2.62, nicotine tablet (OR) 2.06, 95% CI 169–2.62, and for gum (OR) 1.71, 95% CI 1.35–2.21. Though OR of 2.71 in case of nicotine inhaler favors its effectiveness over placebo, but this result remained inconclusive as the 95% CI, in this case, includes unity (0.95–5.43). On the contrary, when all the seven interventions were analyzed by putting them all together, all of them were found to be effective than a placebo. When varenicline was compared against bupropion (control arm), the former was found to be superior in its effect on smoking cessation than the latter with (OR 2.18, 95 CI% 1.09–4.08).
Interpretation: The interventional products used for smoking abstinence for 6 and 12 months, namely varenicline, bupropion, and 5 nicotine replacement therapies like nicotine gum, inhaler, transdermal patch, tablet, and lozenges were all found to be effective than placebo.
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