Cost-Effectiveness Analysis of Smoking Cessation Interventions in the United Kingdom Accounting for Major Neuropsychiatric Adverse Events.

OBJECTIVES: Smoking is a leading cause of death worldwide. Cessation aids include varenicline, bupropion, nicotine replacement therapy (NRT), and e-cigarettes at various doses (low, standard and high) and used alone or in combination with each other. Previous cost-effectiveness analyses have not fully accounted for adverse effects nor compared all cessation aids. The objective was to determine the relative cost-effectiveness of cessation aids in the United Kingdom. METHODS: An established Markov cohort model was adapted to incorporate health outcomes and costs due to depression and self-harm associated with cessation aids, alongside other health events. Relative efficacy in terms of abstinence and major adverse neuropsychiatric events was informed by a systematic review and network meta-analysis. Base case results are reported for UK-licensed interventions only. Two sensitivity analyses are reported, one including unlicensed interventions and another comparing all cessation aids but removing the impact of depression and self-harm. The sensitivity of conclusions to model inputs was assessed by calculating the expected value of partial perfect information. RESULTS: When limited to UK-licensed interventions, varenicline standard-dose and NRT standard-dose were most cost-effective. Including unlicensed interventions, e-cigarette low-dose appeared most cost-effective followed by varenicline standard-dose + bupropion standard-dose combined. When the impact of depression and self-harm was excluded, varenicline standard-dose + NRT standard-dose was most cost-effective, followed by varenicline low-dose + NRT standard-dose. CONCLUSION: Although found to be most cost-effective, combined therapy is currently unlicensed in the United Kingdom and the safety of e-cigarettes remains uncertain. The value-of-information analysis suggested researchers should continue to investigate the long-term effectiveness and safety outcomes of e-cigarettes in studies with active comparators.

Pharmacovigilance Assessment of Cardiac Implications of Nicotine Replacement Therapy Among Smokers.

PURPOSE: The purpose of this quantitative comparative study was to examine the possible relationship between nicotine replacement therapy (NRT) and cardiac disorder risk by comparing the rates of cardiac disorder risk of NRT with cardiac disorder risk of non-replacement drugs among smokers seeking smoking cessation. METHODS: The study used retrospective quantitative design, which involved the collection of secondary data from the adverse event reporting system (FAERS) database of the U.S Food and Drug Administration (FDA). Rates of cardiac disorder were compared between the NRT group and non- NRT (varenicline and bupropion) group. Statistical analyses involved using a 2x2 contingency table and logistic regression to calculate odds ratio (reporting odds ratio (ROR)). RESULTS AND DISCUSSION: Unadjusted ROR was 0.45 (95% confidence interval [CI] 0.28, 0.70). With age and sex as confounding factors, the smokers in the NRT group still had lower odds of having cardiac disorder risk than the non-NRT group (adjusted ROR=0.44, 95% CI 0.28, 0.70). CONCLUSION: Our study findings showed lower cardiac disorder risk with the NRT group compared to the non-NRT (varenicline and bupropion) group. While the study did not aim to undermine either using NRT or non-NRT for smoking cessation therapy to prevent smoking illness, the study results offer informed findings that could potentially improve current smoking cessation management using NRT intervention among smokers and enhance smokers' health outcome. Despite the negative signal detection of cardiac disorder risk with NRT as compared to non-NRT in final findings, we still recommend further research on the causal relationship between NRT and non-NRT and cardiac disorder risk.

Varenicline and Nicotine Replacement Use Associated With US Food and Drug Administration Drug Safety Communications.

Importance: Drug safety communications released by the US Food and Drug Administration (FDA) are often based on limited evidence on safety signals after approval. Varenicline may serve as a relevant case study because it was the target of several FDA communications in 2008 and 2009; ultimately, the Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) dismissed safety concerns on increased suicidal thoughts and aggressive and erratic behavior on December 16, 2016. Objective: To examine the association between FDA drug safety communications and the use of varenicline. Design, Setting, and Participants: Retrospective, longitudinal, cross-sectional study of Veterans Health Administration (VHA) outpatient data from October 1, 2001, through December 31, 2018, and Medicaid drug state use data from July 1, 2006, through September 30, 2018, on varenicline prescribing. Main Outcomes and Measures: Prescribing records for varenicline and nicotine replacement therapy (NRT) in the VHA were extracted, and the number of unique varenicline and NRT users in the VHA per quarter was measured. An interrupted time series analysis was performed to describe the association between FDA safety warnings and the use of varenicline and NRT. To test the generalizability of the findings, similar analyses were conducted using the number of prescriptions reimbursed for varenicline by Medicaid every quarter in 2006-2018. Results: After its addition to the VHA national drug formulary in January 2007, varenicline use presented a steady increase, reaching a peak of 32 581 quarterly unique users in the first quarter of 2008. Within 12 months of the February 1, 2008, public health advisory, quarterly varenicline use in VHA patients decreased by 68.7% (from 32 581 to 10 182 patients; P < .001 for slope change), and NRT use increased by 32.1% (from 55 728 to 73 629 patients; P < .001 for slope change). In Medicaid prescriptions, varenicline use decreased by 38.0% (from 109 308 to 67 761 prescriptions; P < .001 for slope change) within 12 months of the 2008 public health advisory. Twelve months after the publication of the EAGLES trial, which showed no significant increase in psychiatric/behavioral effects with varenicline relative to NRT, use of varenicline increased by 42.7% in VHA patients (from 9251 to 13 199 patients; P = .01 for slope change) and by 26.0% in Medicaid prescriptions (112 063 to 141 122; P = .26 for slope change ). Conclusions and Relevance: With use of varenicline as a case study, early communications from the FDA and VHA followed by a labeling change appeared to be associated with a considerable decrease in drug use, which may have been associated with negative public health consequences.

Reduced adolescent risk-assessment and lower nicotinic beta-2 expression in rats exposed to nicotine through lactation by forcedly drinking dams.

Few animal studies focus on consequences of nicotine postnatal exposure, particularly through lactation. We have recently shown that forced nicotine drinking elevates maternal care, paradoxically provoking arousal and stress in pups. Present work aimed to evaluate the specific contribution of altered maternal cares, compared to the sequelae merely due to nicotine effects. Two groups were compared to water-drinking control dams: (i) free-choice dams (H2O+NIC group) drinking from two bottles, containing either nicotine or water; (ii) forced dams (NIC+NIC group) drinking from two bottles, both containing nicotine. We previously demonstrated that nicotine was indeed transferred to the lactating offspring. Regarding behavioural consequences at adolescence, both H2O+NIC and NIC+NIC rats were slower than controls in discovering a novel over a familiar compartment, whilst only NIC+NIC rats exhibited reduced risk-related avoidance and assessment behaviour. Brain analyses at adulthood suggest that, in prefrontal cortex, nicotine per se reduced serotonin, while the maternal overcare reduced CHRN-B2 gene-expression. As a whole, unescapable nicotine-enhanced maternal care could have an impact on the offspring arousal by acting on prefrontal CHRN-B2 gene-expression. When present results are translated to consequences of non-voluntary exposure in humans, we propose that children receiving altered attentions by a smoking caregiver might undergo a neuro-behavioural development biased towards emotional shyness.

Self-initiated gradual smoking reduction among community correction smokers.

INTRODUCTION: Smoking remains the leading cause of preventable death in the United States. Many smoking cessation guidelines advise smokers to quit precipitately; however, most quit attempts involve a more gradual cessation. Characteristics of individuals who tend to reduce prior to quitting and the effectiveness of pre-quit reduction are not well understood. This study examined individual differences and smoking cessation outcomes between individuals who self-initiated gradual reduction in cigarettes per day (CPD) and those who did not reduce prior to quit date. METHODS: This study is a secondary analysis from a randomized clinical trial of smoking cessation with pharmacotherapy among individuals under community corrections supervision. We compared participants who self-initiated smoking reduction by at least 25% between baseline and the first treatment session (n = 128) to participants who either increased or did not reduce smoking between baseline and the first treatment session (n = 354). RESULTS: African American race, no previous cigar smoking, no previous use of pharmacotherapy for smoking cessation, less withdrawal symptoms at baseline, and older age at first smoking were associated with being a self-initiated gradual reduction in univariate analyses. Individuals who self-initiated gradual reduction also had a had a greater likelihood of achieving at least one quit during the one-year study period as compared to those who did not reduce prior to the intervention. CONCLUSIONS: Individuals who self-initiate gradual reduction differ from those who increase or do not change their smoking prior to a quit date. Gradual reduction also increased success in quitting.

Prevalence of withdrawal symptoms from electronic cigarette cessation: A cross-sectional analysis of the US Population Assessment of Tobacco and Health.

Electronic cigarette use can produce rapid and high levels of nicotine and thus could produce or maintain a physical dependence on nicotine. No experimental and limited observational studies have tested whether cessation of e-cigarettes is associated with withdrawal symptoms. To examine withdrawal from electronic cigarettes and compare it to that from tobacco cigarettes, we searched the US Population Assessment of Tobacco and Health Survey to locate successful and unsuccessful attempts to stop electronic or tobacco cigarettes. We examined electronic cigarette-only users, tobacco cigarette-only users and dual users. A minority of e-cigarette users who stopped/reduced e-cigarettes reported withdrawal symptoms but reported fewer symptoms than tobacco cigarette users who stopped/reduced tobacco cigarettes. E-cigarette withdrawal was not significantly greater in those who tried but were unable to stop e-cigarettes. In dual users, continued tobacco use appeared to reduce e-cigarette withdrawal but the opposite was not true. Given our small sample size and use of retrospective recall, an experimental test of e-cigarette abstinence is needed to better describe the severity of electronic cigarette withdrawal.

Immunological and toxicological risk assessment of e-cigarettes.

Knowledge of the long-term toxicological and immunological effects of e-cigarette (e-cig) aerosols remains elusive due to the relatively short existence of vaping. Therefore, we performed a systematic search of articles published in public databases and analysed the research evidence in order to provide critical information regarding e-cig safety. Electronic nicotine delivery systems (or e-cigs) are an alternative to traditional cigarettes for the delivery of nicotine and are typically filled with glycerol or propylene glycol-based solutions known as e-liquids. Though present in lower quantities, e-cig aerosols are known to contain many of the harmful chemicals found in tobacco smoke. However, due to the paucity of experimental data and contradictory evidence, it is difficult to draw conclusive outcomes regarding toxicological, immunological and clinical impacts of e-cig aerosols. Excessive vaping has been reported to induce inflammatory responses including mitogen-activated protein kinase, Janus tyrosine kinase/signal transducer and activator of transcription and nuclear factor-κB signalling, similar to that induced by tobacco smoke. Based on recent evidence, prolonged exposure to some constituents of e-cig aerosols might result in respiratory complications such as asthma, chronic obstructive pulmonary disease and inflammation. Future studies are warranted that focus on establishing correlations between e-cig types, generations and e-liquid flavours and immunological and toxicological profiles to broaden our understanding about the effects of vaping.

Reduced nicotine content cigarettes in smokers of low socioeconomic status: study protocol for a randomized control trial.

BACKGROUND: The Family Smoking Prevention and Tobacco Control Act gave the Food and Drug Administration jurisdiction over the regulation of all tobacco products, including their nicotine content. Under this act, a major strategy to reduce harm from cigarette tobacco is lowering the nicotine content without causing unintended adverse consequences. Initial research on reduced nicotine content (RNC) cigarettes has shown that smokers of these cigarettes gradually decrease their smoking frequency and biomarkers of exposure. The effectiveness of this strategy needs to be demonstrated in different populations whose response to RNC cigarettes might be substantially mediated by personal or environmental factors, such as low socioeconomic status (SES) populations. This study aims to evaluate the response to a reduced nicotine intervention in low SES smokers, as defined here as those with less than 16 years of education, by switching smokers from high nicotine commercial cigarettes to RNC cigarettes. METHODS/DESIGN: Adults (N = 280) who have smoked five cigarettes or more per day for the past year, have not made a quit attempt in the prior month, are not planning to quit, and have less than 16 years of education are recruited into a two-arm, double-blinded randomized controlled trial. First, participants smoke their usual brand of cigarettes for 1 week and SPECTRUM research cigarettes containing a usual amount of nicotine for 2 weeks. During the experimental phase, participants are randomized to continue smoking SPECTRUM research cigarettes that contain either (1) usual nicotine content (UNC) (11.6 mg/cigarette) or (2) RNC (11.6 to 0.2 mg/cigarette) over 18 weeks. During the final phase of the study, all participants are offered the choice to quit smoking with nicotine replacement therapy, continue smoking the research cigarettes, or return to their usual brand of cigarettes. The primary outcomes of the study include retention rates and compliance with using only research cigarettes and no use of other nicotine-containing products. Secondary outcomes are tobacco smoke biomarkers, nicotine dependence measures, smoking topography, stress levels, and adverse health consequences. DISCUSSION: Results from this study will provide information on whether low SES smokers can maintain a course of progressive nicotine reduction without increases in incidence of adverse effects. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01928719 . Registered on 21 August 2013.

How do smoking cessation medicines compare with respect to their neuropsychiatric safety? A protocol for a systematic review, network meta-analysis and cost-effectiveness analysis.

INTRODUCTION: Cigarette smoking is one of the leading causes of early death in the UK and worldwide. Public health guidance recommends the use of varenicline, bupropion and nicotine replacement therapy (NRT) as smoking cessation aids in the UK. Additionally, the first electronic cigarette has been licensed for use as a smoking cessation medicine. However, there are ongoing concerns about the safety of these medicines. We present a protocol for a systematic review and network meta-analysis (NMA) to determine how these smoking cessation medicines compare to each other with respect to their neuropsychiatric safety in adult smokers. Secondary aims include updating the evidence regarding the effectiveness and cardiovascular safety of these medicines for use in a cost-effectiveness analysis. METHODS AND ANALYSIS: We will include randomised controlled trials and observational studies with control groups comparing monotherapy with varenicline, bupropion, NRT or electronic cigarette and combination therapies to each other, placebo or usual care. The primary composite safety outcome will be serious adverse events, defined as events that resulted in death, were life threatening, required hospitalisation or resulted in significant disability or congenital/birth defect. The preferred effectiveness outcome will be sustained smoking cessation defined as abstinence for a minimum of 6 months as determined by biochemical validation. We will include trials identified by previous reviews and search relevant databases for newly published trials as well as contacting study authors to identify unpublished information. We will conduct fixed-effect and random-effect meta-analyses for each pairwise comparison of treatments and outcome; where these estimates differ, we will consider reasons for heterogeneity, quantified using the between-study variance (τ2). For each outcome, we will construct a NMA in a Bayesian framework which will be compared with the pair-wise results, allowing us to rank treatments. The effectiveness estimates from the NMA will be entered into a probabilistic economic model. ETHICS AND DISSEMINATION: Ethics approval is not required for this evidence synthesis study as it involves analysis of secondary data from randomised controlled trials and observational studies. The review will make an important contribution to the knowledge base around the effectiveness, safety and cost-effectiveness of smoking cessation medicines. Results will be disseminated to the general public, healthcare practitioners and clinicians, academics, industry and policy makers. PROSPERO REGISTRATION NUMBER: CRD42016041302.

Consumer preferences for electronic cigarettes: results from a discrete choice experiment.

INTRODUCTION: E-cigarettes present a formidable challenge to regulators given their variety and the rapidly evolving nicotine market. The current study sought to examine the influence of e-cigarette product characteristics on consumer perceptions and trial intentions among Canadians. METHODS: An online discrete choice experiment was conducted with 915 Canadians aged 16 years and older in November 2013. An online commercial panel was used to sample 3 distinct subpopulations: (1) non-smoking youth and young adults (n=279); (2) smoking youth and young adults (n=264) and (3) smoking adults (n=372). Participants completed a series of stated-preference tasks, in which they viewed choice sets with e-cigarette product images that featured different combinations of attributes: flavour, nicotine content, health warnings and price. For each choice set, participants were asked to select one of the products or indicate 'none of the above' with respect to the following outcomes: interest in trying, less harm and usefulness in quitting smoking. The attributes' impact on consumer choice for each outcome was analysed using multinomial logit regression. RESULTS: Health warning was the most important attribute influencing participants' intentions to try e-cigarettes (42%) and perceived efficacy as a quit aid (39%). Both flavour (36%) and health warnings (35%) significantly predicted perceptions of product harm. CONCLUSIONS: The findings indicate that consumers make trade-offs with respect to e-cigarette product characteristics, and that these trade-offs vary across different subpopulations. Given that health warnings and flavour were weighted most important by consumers in this study, these may represent good targets for e-cigarette regulatory frameworks.

Quantifying how smokers value attributes of electronic cigarettes.

INTRODUCTION: Rates of electronic cigarette (e-cigarette) use have increased quickly among US adults (3.3% in 2010 to 8.5% in 2013) and youth (4.5% in 2013 to 13.4% in 2014). As state and local governments consider regulatory policies, understanding what smokers believe about e-cigarettes and how they value e-cigarettes is important. METHODS: Using data from a convenience sample of Florida adult smokers (N=765), we investigated the value smokers place on specific attributes of e-cigarettes (availability of flavours, effectiveness of e-cigarettes as a cessation aid, healthier alternative to regular cigarettes, ability to use e-cigarettes in public places) by asking smokers how much they would be willing to pay for e-cigarettes with and without each of these attributes. RESULTS: For cigarette-only and dual users, losing the ability to use an e-cigarette as a quit aid and losing the harm reduction of an e-cigarette significantly reduced the price respondents were willing to pay for an e-cigarette. For cigarette-only users, not being able to use an e-cigarette indoors and losing flavours also significantly reduced the price respondents were willing to pay for an e-cigarette. CONCLUSION: Our results suggest that smokers value multiple attributes of e-cigarettes. Our valuation measures also appear to align with smokers' beliefs about e-cigarettes.

What are the effects of varenicline compared with nicotine replacement therapy on long-term smoking cessation and clinically important outcomes? Protocol for a prospective cohort study.

INTRODUCTION: Smoking is a major avoidable cause of ill-health and premature death. Treatments that help patients successfully quit smoking have an important effect on health and life expectancy. Varenicline is a medication that can help smokers successfully quit smoking. However, there are concerns that it may cause adverse effects, such as increase in the occurrence of depression, self-harm and suicide and cardiovascular disease. In this study we aim to examine the effects of varenicline versus other smoking cessation pharmacotherapies on smoking cessation, health service use, all-cause and cause-specific mortality and physical and mental health conditions. METHODS: In this project we will investigate the effects of varenicline compared to nicotine replacement therapies on: (1) long-term smoking cessation and whether these effects differ by area level deprivation; and (2) the following clinically-important outcomes: rate of general practice and hospital attendance; all-cause mortality and death due to diseases of the respiratory system and cardiovascular disease; and a primary care diagnosis of respiratory illness, myocardial infarction or depression and anxiety. The study is based on a cohort of patients prescribed these smoking cessation medications from the Clinical Practice Research Datalink (CPRD). We will use three methods to overcome confounding: multivariable adjusted Cox regression, propensity score matched Cox regression, and instrumental variable regression. The total expected sample size for analysis will be at least 180,000. Follow-up will end with the earliest of either an 'event' or censoring due to the end of registration or death. ETHICS AND DISSEMINATION: Ethics approval was not required for this study. This project has been approved by the CPRD's Independent Scientific Advisory Committee (ISAC). We will disseminate our findings via publications in international peer-reviewed journals and presentations at international conferences.

Behavioral and Pharmacotherapy Interventions for Tobacco Smoking Cessation in Adults, Including Pregnant Women: U.S. Preventive Services Task Force Recommendation Statement.

DESCRIPTION: Update of the 2009 U.S. Preventive Services Task Force (USPSTF) recommendation on counseling and interventions to prevent tobacco use and tobacco-related disease in adults, including pregnant women. METHODS: The USPSTF reviewed the evidence on interventions for tobacco smoking cessation that are relevant to primary care (behavioral interventions, pharmacotherapy, and complementary or alternative therapy) in adults, including pregnant women. POPULATION: This recommendation applies to adults aged 18 years or older, including pregnant women. RECOMMENDATIONS: The USPSTF recommends that clinicians ask all adults about tobacco use, advise them to stop using tobacco, and provide behavioral interventions and U.S. Food and Drug Administration-approved pharmacotherapy for cessation to adults who use tobacco. (A recommendation). The USPSTF recommends that clinicians ask all pregnant women about tobacco use, advise them to stop using tobacco, and provide behavioral interventions for cessation to pregnant women who use tobacco. (A recommendation). The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of pharmacotherapy interventions for tobacco cessation in pregnant women. (I statement). The USPSTF concludes that the current evidence is insufficient to recommend electronic nicotine delivery systems for tobacco cessation in adults, including pregnant women. The USPSTF recommends that clinicians direct patients who smoke tobacco to other cessation interventions with established effectiveness and safety (previously stated). (I statement).

Cardiovascular and mortality risks in older Medicare patients treated with varenicline or bupropion for smoking cessation: an observational cohort study.

PURPOSE: To compare cardiovascular and mortality risks in elderly patients treated with varenicline or bupropion for smoking cessation. METHODS: Elderly Medicare beneficiaries were entered into new-user cohorts of varenicline or bupropion for smoking cessation and followed on therapy for primary outcomes of acute myocardial infarction (AMI), stroke, mortality, and a composite of any of these events. Secondary outcomes were unstable angina, coronary revascularization, and a composite of any primary or secondary outcome event. Propensity score stratification was used to adjust for baseline differences in potential confounding factors. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards, with bupropion as reference. RESULTS: In cohorts of 74 824 varenicline and 14 133 bupropion users, there were 164 AMI, 96 stroke, 87 death, 317 primary composite, and 814 secondary composite events while on therapy. The HRs (95%CI) were 0.79 (0.50-1.24) for AMI, 1.27 (0.63-2.55) for stroke, 0.58 (0.30-1.13) for death, 0.84 (0.58-1.23) for the primary composite, and 0.92 (0.73-1.14) for the secondary composite. The risk of AMI or the primary composite outcome did not differ in subgroups defined by age, diabetes status, or presence of underlying ischemic heart disease. Only 30% of patients remained on either study drug beyond their first prescription. CONCLUSION: Cardiovascular and mortality risks were not increased in older patients treated with varenicline compared with bupropion for smoking cessation. A potential increase in the risk of stroke with varenicline could not be excluded. Treatment persistence with either drug was low. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

What is the clinical effectiveness and cost-effectiveness of cytisine compared with varenicline for smoking cessation? A systematic review and economic evaluation.

BACKGROUND: Tobacco smoking is one of the leading causes of deaths worldwide. Nearly one-fifth of adults in the UK regularly smoke cigarettes. The ill-health associated with smoking costs the NHS over £3B every year. A number of pharmacological interventions are available that can help people to quit smoking. These include nicotinic receptor partial agonists such as varenicline or cytisine. Varenicline is a synthetic product licensed for use in the UK, while cytisine is derived naturally from the seeds of the plant Cytisus laborinum L. (golden rain acacia). OBJECTIVES: To review the evidence on the clinical effectiveness and safety of cytisine from smoking cessation compared with varenicline; to develop an economic model to estimate the cost-effectiveness of cytisine and varenicline; and to provide recommendations based on value of information analyses as to whether or not a head-to-head trial of cytisine and varenicline would represent effective use of resources. DATA SOURCES: Efficacy and adverse events data were sourced from a recent Cochrane review. These data were supplemented with an updated search of twelve electronic databases, including MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature and The Cochrane Library, for the period from December 2011 to January 2013. The review included randomised controlled trials (RCTs) of adult smokers attempting to quit using varenicline or cytisine. Further interventions were considered (placebo, nicotine replacement therapy, bupropion) to allow an indirect comparison between varenicline and cytisine. The primary outcome was abstinence at a minimum of 6 months' follow-up. Secondary outcomes were common adverse events such as abnormal dreams, headache, nausea, insomnia and serious adverse events. REVIEW METHODS: A systematic review and network meta-analysis of the clinical evidence was undertaken. A random-effects model was used to allow for heterogeneity between studies. The economic model structure was based on a published model. Probabilistic sensitivity analyses were undertaken to estimate the treatment expected to be most cost-effective given current information. Formal expected value of perfect information, perfect partial information and of sample information were performed. RESULTS: Twenty-three (RCTs) were included in the systematic review, comprising a total of 10,610 participants. Twenty-one trials of varenicline of differing dosing schedules and two trials of cytisine at standard dose met the inclusion criteria. No head-to-head trials comparing varenicline with cytisine were identified. The methodological quality of the studies was judged to be moderate to good. Cytisine was more efficacious than placebo [hazard ratio (HR) 4.27, 95% credible interval (CrI) 2.05 to 10.05], as was standard-dose varenicline (HR 2.58, 95% Crl 2.16 to 3.15). Standard-dose varenicline treatment was associated with significantly higher rates of headache, insomnia and nausea than placebo; there was no significant difference in the rates of abnormal dreams. There were no significant differences in the rates of headache or nausea between cytisine and placebo; data were identified for neither abnormal dreams nor insomnia. Using expected values, cytisine is anticipated to dominate varenicline, in that it produces more quality-adjusted life-years at a lower associated cost. This occurred in approximately 90% of the scenarios performed. However, owing to the large number of people who wish to quit smoking (estimated to be 3 million over a 10-year period), the implications of making an incorrect decision is large. The expected value of sample information indicated that conducting a head-to-head trial of cytisine and varenicline was worthwhile, and that 1000 smokers per arm was an appropriate number to recruit. CONCLUSIONS: On the basis of the evidence included in this review, varenicline and cytisine are both effective interventions to aid smoking cessation when compared with placebo. Cytisine is estimated to be both more clinically effective and cost-effective than varenicline. However, there is uncertainty in the decision, and a head-to-head trial of cytisine and varenicline would appear to be an effective use of resources. STUDY REGISTRATION: The study was registered as PROSPERO CRD42012003455. FUNDING DETAILS: The National Institute for Health Research Health Technology Assessment programme.