Estimation of risk of neuropsychiatric adverse events from varenicline, bupropion and nicotine patch versus placebo: secondary analysis of results from the EAGLES trial using Bayes factors.

BACKGROUND AND AIMS: Analysed using classical frequentist hypothesis testing with alpha set to 0.05, the Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) did not find enough evidence to reject the hypothesis of no difference in neuropsychiatric adverse events (NPSAEs) attributable to varenicline, bupropion, or nicotine patch compared with placebo. This might be because the null hypothesis was true or because the data were insensitive. The present study aimed to test the hypothesis more directly using Bayes factors. DESIGN: EAGLES was a randomised, double-blind, triple-dummy, controlled trial. SETTING: Global (16 countries across five continents), between November 2011 and January 2015. PARTICIPANTS: Participants were smokers with (n = 4116) and without (n = 4028) psychiatric disorders. INTERVENTIONS: Varenicline (1 mg twice daily), bupropion (150 mg twice daily), nicotine patch (21 mg once daily with taper) and matched placebos. MEASUREMENTS: The outcomes included: (i) a composite measure of moderate/severe NPSAEs; and (ii) a composite measure of severe NPSAEs. The relative evidence for there being no difference in NPSAEs versus data insensitivity for the medications was calculated in the full and sub-samples using Bayes factors and corresponding robustness regions. FINDINGS: For all but two comparisons, Bayes factors were <1/3, indicating moderate to strong evidence for no difference in risk of NPSAEs between active medications and placebo (Bayes factor = 0.02-0.23). In the psychiatric cohort versus placebo, the data were suggestive, but not conclusive of no increase in NPSAEs with varenicline (Bayes factor = 0.52) and bupropion (Bayes factor = 0.71). Here, the robustness regions ruled out a ≥7% and ≥8% risk increase with varenicline and bupropion, respectively. CONCLUSIONS: Secondary analysis of the Evaluating Adverse Events in a Global Smoking Cessation Study trial using Bayes factors provides moderate to strong evidence that use of varenicline, bupropion or nicotine patches for smoking cessation does not increase the risk of neuropsychiatric adverse events relative to use of placebo in smokers without a history of psychiatric disorder. For smokers with a history of psychiatric disorder the evidence also points to no increased risk but with less confidence.

Safety and efficacy of first-line smoking cessation pharmacotherapies in bipolar disorders: Subgroup analysis of a randomized clinical trial.

OBJECTIVES: Post hoc analyses of EAGLES data to examine safety and efficacy of first-line smoking cessation pharmacotherapies in smokers with bipolar disorders (BD). METHODS: Smokers with BD I/II (n = 285; 81.4% with BD I) and a comparison nonpsychiatric cohort (NPC; n = 2794) were randomly assigned to varenicline, bupropion, nicotine replacement therapy (NRT), or placebo for 12 weeks, plus weekly counseling. Primary outcomes were occurrence of moderate to severe neuropsychiatric adverse events (NPSAEs) and Weeks 9-12 biochemically-confirmed continuous abstinence (CA) rates. RESULTS: For BD smokers, NPSAE risk differences versus placebo were: varenicline, 6.17 (95% CI: -7.84 to 20.18); bupropion, 4.09 (-8.82 to 16.99); NRT, -0.56 (-12.34 to 11.22). ORs for Weeks 9-12 CA, comparing active medication to placebo among BD smokers were: varenicline, 2.61 (0.68-9.95); bupropion, 1.29 (0.31-5.37), NRT, 0.71 (0.14-3.74). Pooling across treatments, NPSAE occurrence was higher (10.7% versus 2.3%; P < 0.001) and CA rates were lower (22.8% versus 13.3%; P = 0.008) in BD than NPC. LIMITATIONS: Study not powered to detect differences in safety and efficacy in the BD subcohort; generalizability limited to stably treated BD without current substance use disorders. CONCLUSIONS: Smokers with BD had higher risk of NPSAEs and were less likely to quit overall than NPC smokers. Among smokers with BD, NPSAE risk difference estimates for active treatments versus placebo ranged from 1% lower to 6% higher. Efficacy of varenicline in smokers with BD was similar to EAGLES main outcomes; bupropion and NRT effect sizes were descriptively lower. Varenicline may be a tolerable and effective cessation treatment for smokers with BD. TRIAL REGISTRATION: ClinicalTrials.gov identifier (https://clinicaltrials.gov/): NCT01456936.