Cardiovascular Safety of Varenicline: Patient-Level Meta-Analysis of Randomized, Blinded, Placebo-Controlled Trials

Obstructive Sleep Apnea and Smoking Increase the Risk of Cardiovascular Disease: Smoking Cessation Pharmacotherapy

Tobacco smoking has been a recognized risk factor for cardiovascular diseases (CVD). Smoking is a chronic relapsing disease and pharmacotherapy is a main component of smoking cessation. Obstructive sleep apnea (OSA) and smoking both increase the risk of CVD and are associated with significant morbidity and mortality. There are few existing data examining how pharmacological treatment, such as nicotine replacement therapy (NRT), bupropion, and varenicline, affect smokers suffering with OSA and especially their cardiovascular effects. The aim of this review was to evaluate the effects of smoking cessation pharmacotherapy on OSA with a special emphasis on the cardiovascular system. Results: Only small studies have assessed the effect of NRTs on OSA. Nicotine gum administration showed an improvement in respiratory events but with no permanent results. No specific studies were found on the effect of bupropion on OSA, and a limited number evaluated varenicline's effects on sleep and specifically OSA. Varenicline administration in smokers suffering from OSA reduced the obstructive respiratory events, especially during REM. Studies on second-line medication (nortriptyline, clonidine, cytisine) are even more limited. There are still no studies evaluating the cardiovascular effects of smoking cessation medications on OSA patients. Conclusions: Sleep disturbances are common withdrawal effects during smoking cessation but could be also attributed to pharmacotherapy. Smokers should receive personalized treatment during their quitting attempts according to their individual needs and problems, including OSA. Future studies are needed in order to evaluate the efficacy and safety of smoking cessation medications in OSA patients.

The utility of the self-controlled study design for pharmacoepidemiological studies without an active comparator medication using a medical information database: An application to assess the risk of varenicline on cardiovascular outcomes

PURPOSE

To illustrate the utility of the self-controlled study design for studies without an active comparator, we compared the results of a cohort design study with a non-user comparator with those of a self-controlled design study in evaluating the risk of varenicline on cardiovascular outcomes, using a Japanese medical claims database.

METHODS

The participating smokers were identified from health-screening results collected between May 2008 and April 2017. Using a non-user-comparator cohort study design, we estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) of varenicline on initial hospitalization with cardiovascular outcomes using Cox's model adjusted for patients' sex, age, medical history, medication history, and health-screening results. Using a self-controlled study design, the within-subject HR was estimated using a stratified Cox's model adjusted for medical history, medication history, and health-screening results. The estimate from a recent meta-analysis was considered the gold standard (risk ratio: 1.03).

RESULTS

We identified 460 464 smokers (398 694 males [86.6%]; mean (standard deviation) age: 42.9 [10.8] years) in the database. Of these, 11 561 had been dispensed varenicline at least once, and 4511 had experienced cardiovascular outcomes. The estimate of the non-user-comparator cohort study design exceeded the gold standard (HR [95% CI]: 2.04 [1.22-3.42]), whereas that of the self-controlled study design was close to the gold standard (within-subject HR [95% CI]: 1.12 [0.27-4.70]).

CONCLUSIONS

The self-controlled study design is useful alternative to a non-user-comparator cohort design when evaluating the risk of medications relative to their non-use, based on a medical information database.

Clinical Practice Guideline of Spanish Society of Pneumology and Thoracic Surgery (SEPAR) on Pharmacological Treatment of Tobacco Dependence 2023

INTRODUCTION

There are multiple systematic reviews and meta-analyses on the efficacy and safety of pharmacological treatments against nicotine dependence. However, there are few guidelines to answer frequent questions asked by a clinician treating a smoker. Therefore, the aim of this paper is to facilitate the treatment of tobacco addiction.

MATERIAL AND METHODS

12 PICO questions are formulated from a GLOBAL PICO question: "Efficacy and safety of pharmacological treatment of tobacco dependence". A systematic review was carried out to answer each of the questions and recommendations were made. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system was used to grade the certainty of the estimated effects and the strength of the recommendations.

RESULTS

Varenicline, nicotine replacement therapy (NRT), bupropion and cytisine are more effective than placebo. Varenicline and combined nicotine therapy are superior to the other therapies. In smokers with high dependence, a combination of drugs is recommended, being more effective those associations containing varenicline. Other optimization strategies with lower efficacy consist of increasing the doses, the duration, or retreat with varenicline. In specific populations varenicline or NRT is recommended. In hospitalized, the treatment of choice is NRT. In pregnancy it is indicated to prioritize behavioral treatment. The financing of smoking cessation treatments increases the number of smokers who quit smoking. There is no scientific evidence of the efficacy of pharmacological treatment of smoking cessation in adolescents.

CONCLUSIONS

The answers to the 12 questions allow us to extract recommendations and algorithms for the pharmacological treatment of tobacco dependence.

Abstinence Rate, Adverse Events and Withdrawal Symptoms after Varenicline Use and Predicting Factors of Smoking Abstinence: A Multicentre Single-State Study in Malaysia

(1) Background: Varenicline is a widely prescribed agent in smoking cessation. However, the abstinence rate, the incidence of adverse events and withdrawal symptoms, have not been widely studied locally. This study aimed to determine the prevalence of smoking abstinence, adverse events and withdrawal symptoms associated with varenicline use, as well as possible factors contributing to successful smoking abstinence. (2) Methods: This was a retrospective, cohort study conducted in twenty-two government-operated smoking cessation clinics across the state of Perak, Malaysia. The medical records of adult smokers (age ≥ 18 years old) who were prescribed with varenicline between January 2017 and June 2018 were traced. The medical records of smokers who used pharmacotherapy other than varenicline, those who received less than four weeks of varenicline treatment, and with missing data were excluded. (3) Results: Sixty-eight out of 114 subjects (59.6%) successfully achieved smoking abstinence. Probable varenicline-induced chest pain was documented in three subjects. Altered behaviour (n = 2) and auditory hallucinations (n = 1) were also reported. Varenicline treatment duration is a significant predictive factor for successful smoking abstinence (odds ratio (OR) = 2.45; 95% confidence interval (CI) 1.74−3.45; p < 0.001), followed by age (OR = 1.25; 95% CI 1.005−1.564; p = 0.045), the presence of adverse events (OR = 0.096; 95% CI 0.014−0.644; p = 0.016) and withdrawal symptoms (OR = 0.032; 95% CI 0.016−0.835; p = 0.032). (4) Conclusion: Almost two-thirds of the subjects achieved smoking abstinence with varenicline. The duration of the treatment, as well as the patients’ ages had a significant influence on successful smoking abstinence. Rare cases of cardiovascular and neuropsychiatric-related adverse events were reported, warranting continuous surveillance and adverse drug reaction reporting.

Varenicline: mode of action, efficacy, safety and accumulated experience salient for clinical populations

Objective: Varenicline, a selective partial agonist of the α4β2 nicotinic acetylcholine receptor, is a smoking cessation pharmacotherapy that more than doubles the chance of quitting smoking at 6 months compared with placebo. This article reviews salient knowledge of the discovery, pharmacological characteristics, and the efficacy and safety of varenicline in general and in specific populations of smokers and provides recommendations to support use in clinical practice.Methods: Literature searches for varenicline were conducted using PubMed, with date limitations of 2000-2018 inclusive, using search terms covering the discovery, mechanism of action, pharmacokinetics, efficacy and safety in different populations of smokers, alternative quit approaches and combination therapy. Selection of safety and efficacy data was limited to clinical trials, meta-analyses and observational studies.Results: Standard administration of varenicline is efficacious in helping smokers to quit, including smokers with cardiovascular disease and chronic obstructive pulmonary disease. Furthermore, varenicline efficacy may be improved with pre-loading, a gradual quitting approach for smokers unwilling or unable to quit abruptly, and extended treatment in smokers who have recently quit to help maintain abstinence. Initial concerns regarding the association of varenicline with increased risk of neuropsychiatric and cardiovascular adverse events have been disproven after extensive clinical evaluations, and the benefit-risk profile of varenicline is considered favorable.Conclusions: Varenicline is efficacious and safe for all adult smokers with a range of clinical characteristics. Evidence suggests that approaches offering greater flexibility in timing and duration of treatment may further extend treatment efficacy and clinical reach.

Smoking abstinence 1 year after acute coronary syndrome: follow-up from a randomized controlled trial of varenicline in patients admitted to hospital

BACKGROUND

Patients who continue to smoke after acute coronary syndrome are at increased risk of reinfarction and death. We previously found use of varenicline to increase abstinence 24 weeks after acute coronary syndrome; here we report results through 52 weeks.

METHODS

The EVITA trial was a multicentre, double-blind, randomized, placebo-controlled trial of varenicline for smoking cessation in patients admitted to hospital with acute coronary syndrome. Participants were randomly assigned (1:1) to receive varenicline or placebo for 12 weeks, in conjunction with low-intensity counselling. Smoking abstinence was assessed via 7-day recall, with biochemical validation using exhaled carbon monoxide. Participants lost to follow-up or withdrawn were assumed to have returned to smoking.

RESULTS

Among the 302 participants, abstinence declined over the course of the trial, with 34.4% abstinent 52 weeks after acute coronary syndrome. Compared with placebo, point estimates suggest use of varenicline increased point-prevalence abstinence (39.9% v. 29.1%, difference 10.7%, 95% confidence interval [CI] 0.01% to 21.44%; number needed to treat 10), continuous abstinence (31.1% v. 21.2%, difference 9.9%, 95% CI -0.01% to 19.8%) and reduction in daily cigarette smoking by 50% or greater (57.8% v. 49.7%, difference 8.1%, 95% CI -3.1% to 19.4%). Varenicline and placebo groups had similar occurrence of serious adverse events (24.5% v. 21.9%, risk difference 2.7%, 95% CI -7.3% to 12.6%) and major adverse cardiovascular events (8.6% v. 9.3%, risk difference -0.7%, 95% CI -7.8% to 6.5%).

INTERPRETATION

Varenicline was efficacious for smoking cessation in this high-risk patient population. However, 60% of patients who received treatment with varenicline still returned to smoking. Trial registration: ClinicalTrials.gov, no. NCT00794573.

Big Health Data and Cardiovascular Diseases: A Challenge for Research, an Opportunity for Clinical Care

Cardiovascular disease (CVD) accounts for the majority of death and hospitalization, health care expenditures and loss of productivity in developed country. CVD research, thus, plays a key role for improving patients' outcomes as well as for the sustainability of health systems. The increasing costs and complexity of modern medicine along with the fragmentation in healthcare organizations interfere with improving quality care and represent a missed opportunity for research. The advancement in diagnosis, therapy and prognostic evaluation of patients with CVD, indeed, is frustrated by limited data access to selected small patient populations, not standardized nor computable definition of disease and lack of approved relevant patient-centered outcomes. These critical issues results in a deep mismatch between randomized controlled trials and real-world setting, heterogeneity in treatment response and wide inter-individual variation in prognosis. Big data approach combines millions of people's electronic health records (EHR) from different resources and provides a new methodology expanding data collection in three direction: high volume, wide variety and extreme acquisition speed. Large population studies based on EHR holds much promise due to low costs, diminished study participant burden, and reduced selection bias, thus offering an alternative to traditional ascertainment through biomedical screening and tracing processes. By merging and harmonizing large data sets, the researchers aspire to build algorithms that allow targeted and personalized CVD treatments. In current paper, we provide a critical review of big health data for cardiovascular research, focusing on the opportunities of this largely free data analytics and the challenges in its realization.

Prevention and Treatment of Tobacco Use: JACC Health Promotion Series

Tobacco use is the leading preventable cause of death worldwide and is a major risk factor for cardiovascular disease (CVD). Both prevention of smoking initiation among youth and smoking cessation among established smokers are key for reducing smoking prevalence and the associated negative health consequences. Proven tobacco cessation treatment includes pharmacotherapy and behavioral support, which are most effective when provided together. First-line medications (varenicline, bupropion, and nicotine replacement) are effective and safe for patients with CVD. Clinicians who care for patients with CVD should give as high a priority to treating tobacco use as to managing other CVD risk factors. Broader tobacco control efforts to raise tobacco taxes, adopt smoke-free laws, conduct mass media campaigns, and restrict tobacco marketing enhance clinicians' actions working with individual smokers.

Stimulation of brain nicotinic acetylcholine receptors activates adrenomedullary outflow via brain inducible NO synthase-mediated S-nitrosylation

BACKGROUND AND PURPOSE

We have demonstrated that i.c.v.-administered (±)-epibatidine, a nicotinic ACh receptor (nAChR) agonist, induced secretion of noradrenaline and adrenaline (catecholamines) from the rat adrenal medulla with dihydro-β-erythroidin (an α4β2 nAChR antagonist)-sensitive brain mechanisms. Here, we examined central mechanisms for the (±)-epibatidine-induced responses, focusing on brain NOS and NO-mediated mechanisms, soluble GC (sGC) and protein S-nitrosylation (a posttranslational modification of protein cysteine thiol groups), in urethane-anaesthetized (1.0 g·kg^-1 , i.p.) male Wistar rats.

EXPERIMENTAL APPROACH

(±)-Epibatidine was i.c.v. treated after i.c.v. pretreatment with each inhibitor described below. Then, plasma catecholamines were measured electrochemically after HPLC. Immunoreactivity of S-nitrosylated cysteine (SNO-Cys) in α4 nAChR subunit (α4)-positive spinally projecting neurones in the rat hypothalamic paraventricular nucleus (PVN, a regulatory centre of adrenomedullary outflow) after i.c.v. (±)-epibatidine administration was also investigated.

KEY RESULTS

(±)-Epibatidine-induced elevation of plasma catecholamines was significantly attenuated by L-NAME (non-selective NOS inhibitor), carboxy-PTIO (NO scavenger), BYK191023 [selective inducible NOS (iNOS) inhibitor] and dithiothreitol (thiol-reducing reagent), but not by 3-bromo-7-nitroindazole (selective neuronal NOS inhibitor) or ODQ (sGC inhibitor). (±)-Epibatidine increased the number of spinally projecting PVN neurones with α4- and SNO-Cys-immunoreactivities, and this increment was reduced by BYK191023.

CONCLUSIONS AND IMPLICATIONS

Stimulation of brain nAChRs can induce elevation of plasma catecholamines through brain iNOS-derived NO-mediated protein S-nitrosylation in rats. Therefore, brain nAChRs (at least α4β2 subtype) and NO might be useful targets for alleviation of catecholamines overflow induced by smoking.

Smoking Cessation in Patients With Acute Coronary Syndrome

Over 30% of the nearly 1 million North Americans hospitalized annually with an acute coronary syndrome (ACS) are smokers. Despite a substantially increased risk of morbidity and mortality, 2/3 of patients who quit smoking after ACS return to smoking within 1 year. To summarize the evidence of smoking cessation in patients hospitalized after ACS, we systematically reviewed all randomized controlled trials of pharmacologic and behavioral smoking cessation therapies in patients with ACS. In addition, we reviewed the clinical considerations surrounding the use of smoking cessation therapies, including their broad mechanisms of action and possible alternative treatments, including cardiac rehabilitation programs and electronic cigarettes. A total of 7 randomized controlled trials met our inclusion criteria (4 pharmacotherapies and 3 behavioral therapies). In pharmacologic trials, only varenicline increased point prevalence abstinence at 12 months. Behavioral interventions produced significantly improved abstinence rates at 6 and 12 months. However, these studies had substantial limitations affecting their generalizability. Overall, currently available smoking cessation therapies are limited in their efficacy in patients hospitalized after ACS. Because of the relative scarcity of data and the urgency of establishing clinical guidelines, there is a critical need to continue examining the efficacy and safety of smoking cessation interventions in patients hospitalized after ACS.

Cardiovascular Safety of Varenicline, Bupropion, and Nicotine Patch in Smokers: A Randomized Clinical Trial

IMPORTANCE

Quitting smoking is enhanced by the use of pharmacotherapies, but concerns have been raised regarding the cardiovascular safety of such medications.

OBJECTIVE

To compare the relative cardiovascular safety risk of smoking cessation treatments.

DESIGN, SETTING, AND PARTICIPANTS

A double-blind, randomized, triple-dummy, placebo- and active-controlled trial (Evaluating Adverse Events in a Global Smoking Cessation Study [EAGLES]) and its nontreatment extension trial was conducted at 140 multinational centers. Smokers, with or without established psychiatric diagnoses, who received at least 1 dose of study medication (n = 8058), as well as a subset of those who completed 12 weeks of treatment plus 12 weeks of follow up and agreed to be followed up for an additional 28 weeks (n = 4595), were included.

INTERVENTIONS

Varenicline, 1 mg twice daily; bupropion hydrochloride, 150 mg twice daily; and nicotine replacement therapy, 21-mg/d patch with tapering.

MAIN OUTCOMES AND MEASURES

The primary end point was the time to development of a major adverse cardiovascular event (MACE: cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke) during treatment; secondary end points were the occurrence of MACE and other pertinent cardiovascular events (MACE+: MACE or new-onset or worsening peripheral vascular disease requiring intervention, coronary revascularization, or hospitalization for unstable angina).

RESULTS

Of the 8058 participants, 3553 (44.1%) were male (mean [SD] age, 46.5 [12.3] years). The incidence of cardiovascular events during treatment and follow-up was low (<0.5% for MACE; <0.8% for MACE+) and did not differ significantly by treatment. No significant treatment differences were observed in time to cardiovascular events, blood pressure, or heart rate. There was no significant difference in time to onset of MACE for either varenicline or bupropion treatment vs placebo (varenicline: hazard ratio, 0.29; 95% CI, 0.05-1.68 and bupropion: hazard ratio, 0.50; 95% CI, 0.10-2.50).

CONCLUSIONS AND RELEVANCE

No evidence that the use of smoking cessation pharmacotherapies increased the risk of serious cardiovascular adverse events during or after treatment was observed. The findings of EAGLES and its extension trial provide further evidence that smoking cessation medications do not increase the risk of serious cardiovascular events in the general population of smokers.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01574703.

Efficacy and safety of varenicline for smoking cessation in people living with HIV in France (ANRS 144 Inter-ACTIV): a randomised controlled phase 3 clinical trial

BACKGROUND

Tobacco smoking is common in people living with HIV, but high-quality evidence on interventions for smoking cessation is not available in this population. We aimed to assess the efficacy and safety of varenicline with counselling to aid smoking cessation in people living with HIV.

METHODS

The ANRS 144 Inter-ACTIV randomised, parallel, double-blind, multicentre, placebo-controlled phase 3 trial was done at 30 clinical hospital sites in France. People living with HIV who had smoked at least ten cigarettes per day for 1 year or longer, were motivated to stop smoking, were not dependent on another psychoactive substance, and had no history of depression or suicide attempt were eligible. Using a computer-generated randomisation sequence, we allocated (1:1) the patients to receive either varenicline titrated to two 0·5 mg doses twice daily or placebo twice daily for 12 weeks, plus face-to-face counselling. Patients and investigators were masked to treatment group allocation. Patients who were not abstinent at week 24 were offered open-label varenicline for 12 additional weeks. The primary outcome was the proportion of smokers continuously abstinent from week 9 to week 48. Smoking status was confirmed by carbon monoxide in exhaled air. Primary analyses were done in both the intention-to-treat (ITT) population and modified ITT (mITT) population, which comprised all patients who took at least one tablet of their assigned study treatment. The safety analyses were done in the mITT population. The trial is registered at ClinicalTrials.gov, number NCT00918307. The trial status is complete.

FINDINGS

From Oct 26, 2009, to Dec 20, 2012, of 303 patients assessed for eligibility, 248 patients were randomly assigned to the varenicline group (n=123) or the placebo group (n=125). After randomisation, one participant initially assigned to the placebo group was excluded from the ITT analysis for a regulatory reason (no French health-care coverage). 102 patients in the varenicline group and 111 patients in the placebo group received at least one dose of their assigned treatment and were included in the mITT analysis. In the ITT analysis, varenicline was associated with a higher proportion of patients achieving continuous abstinence over the study period (week 9-48): 18 (15%, 95% CI 8-21) of 123 in the varenicline group versus eight (6%, 2-11) of 124 in the placebo group, adjusted odds ratio (OR) 2·5 (95% CI 1·0-6·1; p=0·041). In the mITT analysis, varenicline was also associated with higher continuous abstinence: 18 (18%, 95% CI 10-25) of 102 versus eight (7%, 2-12) of 111 in the placebo group (adjusted OR 2·7, 95% CI 1·1-6·5; p=0·029). The incidence of depression was 2·4 per 100 person-years (95% CI 0·6-9·5; two [2%] of 102) in the varenicline group and 12·4 per 100 person-years (95% CI 6·9-22·5; 11 [10%] of 111) in the placebo group. 14 (7%) of 213 participants had 18 cardiovascular events: six (6%) of 102 people in the varenicline group and eight (7%) of 111 people in the placebo group.

INTERPRETATION

Varenicline is safe and efficacious for smoking cessation in people living with HIV and should be recommended as the standard of care.

FUNDING

The French National Institute for Health and Medical Research (INSERM)-French National Agency for Research on AIDS and Viral Hepatitis (ANRS) and Pfizer.

Effects of varenicline on sympatho-vagal balance and cue reactivity during smoking withdrawal: a randomised placebo-controlled trial

Background

Varenicline is an effective smoking cessation medication. Some concern has been raised that its use may precipitate adverse cardiovascular events although no patho-physiological mechanism potentially underlying such an effect has been reported. The aim of this study was to test the hypothesis that varenicline impacts on sympatho-vagal balance during smoking withdrawal.

Methods

In this randomised, placebo-controlled trial, muscle sympathetic nerve activity (MSNA), baroreflex sensitivity (BRS), heart rate, and blood pressure were assessed in 17 smokers four weeks before a quit attempt (baseline) and again on the third day of that quit attempt (acute smoking withdrawal).

Results

Regarding the primary endpoint of our study, we did not find a significant effect of varenicline compared to placebo on changes in MSNA burst incidence between baseline and acute smoking withdrawal (−3.0 ± 3.3 vs.−3.9 ± 5.0 bursts/100 heart beats; p = 0.308). However, heart rate and systolic blood pressure significantly decreased in the placebo group only, while no significant changes in these parameters were observed in the varenicline group. Exposure to smoking cues during acute withdrawal lead to a significant increase of heart rate in the placebo group, while heart rate decreased in the varenicline group, and the difference in these changes was significant between groups (+2.7 ± 1.0 vs.−1.8 ± 0.5 1/min; p = 0.002). In all 17 participants combined, a significant increase in heart rate during smoking cue exposure was detected in subjects who relapsed in the course of six weeks after the quit date compared to those who stayed abstinent (+2.5 ± 1.2 vs.−1.1 ± 0.7; p = 0.018). Six-week abstinence rates were higher in the varenicline group compared to placebo (88 vs. 22 % p = 0.015).

Conclusion

We did not find evidence of adverse effects of varenicline on sympatho-vagal balance. Varenicline probably blunts the heart rate response to smoking cues, which may be linked to improved cessation outcome.

Nicotine receptor partial agonists for smoking cessation

BACKGROUND

Nicotine receptor partial agonists may help people to stop smoking by a combination of maintaining moderate levels of dopamine to counteract withdrawal symptoms (acting as an agonist) and reducing smoking satisfaction (acting as an antagonist).

OBJECTIVES

To review the efficacy of nicotine receptor partial agonists, including varenicline and cytisine, for smoking cessation.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's specialised register for trials, using the terms ('cytisine' or 'Tabex' or 'dianicline' or 'varenicline' or 'nicotine receptor partial agonist') in the title or abstract, or as keywords. The register is compiled from searches of MEDLINE, EMBASE, and PsycINFO using MeSH terms and free text to identify controlled trials of interventions for smoking cessation and prevention. We contacted authors of trial reports for additional information where necessary. The latest update of the specialised register was in May 2015, although we have included a few key trials published after this date. We also searched online clinical trials registers.

SELECTION CRITERIA

We included randomised controlled trials which compared the treatment drug with placebo. We also included comparisons with bupropion and nicotine patches where available. We excluded trials which did not report a minimum follow-up period of six months from start of treatment.

DATA COLLECTION AND ANALYSIS

We extracted data on the type of participants, the dose and duration of treatment, the outcome measures, the randomisation procedure, concealment of allocation, and completeness of follow-up.The main outcome measured was abstinence from smoking at longest follow-up. We used the most rigorous definition of abstinence, and preferred biochemically validated rates where they were reported. Where appropriate we pooled risk ratios (RRs), using the Mantel-Haenszel fixed-effect model.

MAIN RESULTS

Two trials of cytisine (937 people) found that more participants taking cytisine stopped smoking compared with placebo at longest follow-up, with a pooled risk ratio (RR) of 3.98 (95% confidence interval (CI) 2.01 to 7.87; low-quality evidence). One recent trial comparing cytisine with NRT in 1310 people found a benefit for cytisine at six months (RR 1.43, 95% CI 1.13 to 1.80).One trial of dianicline (602 people) failed to find evidence that it was effective (RR 1.20, 95% CI 0.82 to 1.75). This drug is no longer in development.We identified 39 trials that tested varenicline, 27 of which contributed to the primary analysis (varenicline versus placebo). Five of these trials also included a bupropion treatment arm. Eight trials compared varenicline with nicotine replacement therapy (NRT). Nine studies tested variations in varenicline dosage, and 13 tested usage in disease-specific subgroups of patients. The included studies covered 25,290 participants, 11,801 of whom used varenicline.The pooled RR for continuous or sustained abstinence at six months or longer for varenicline at standard dosage versus placebo was 2.24 (95% CI 2.06 to 2.43; 27 trials, 12,625 people; high-quality evidence). Varenicline at lower or variable doses was also shown to be effective, with an RR of 2.08 (95% CI 1.56 to 2.78; 4 trials, 1266 people). The pooled RR for varenicline versus bupropion at six months was 1.39 (95% CI 1.25 to 1.54; 5 trials, 5877 people; high-quality evidence). The RR for varenicline versus NRT for abstinence at 24 weeks was 1.25 (95% CI 1.14 to 1.37; 8 trials, 6264 people; moderate-quality evidence). Four trials which tested the use of varenicline beyond the 12-week standard regimen found the drug to be well-tolerated during long-term use. The number needed to treat with varenicline for an additional beneficial outcome, based on the weighted mean control rate, is 11 (95% CI 9 to 13). The most commonly reported adverse effect of varenicline was nausea, which was mostly at mild to moderate levels and usually subsided over time. Our analysis of reported serious adverse events occurring during or after active treatment suggests there may be a 25% increase in the chance of SAEs among people using varenicline (RR 1.25; 95% CI 1.04 to 1.49; 29 trials, 15,370 people; high-quality evidence). These events include comorbidities such as infections, cancers and injuries, and most were considered by the trialists to be unrelated to the treatments. There is also evidence of higher losses to follow-up in the control groups compared with the intervention groups, leading to a likely underascertainment of the true rate of SAEs among the controls. Early concerns about a possible association between varenicline and depressed mood, agitation, and suicidal behaviour or ideation led to the addition of a boxed warning to the labelling in 2008. However, subsequent observational cohort studies and meta-analyses have not confirmed these fears, and the findings of the EAGLES trial do not support a causal link between varenicline and neuropsychiatric disorders, including suicidal ideation and suicidal behaviour. The evidence is not conclusive, however, in people with past or current psychiatric disorders. Concerns have also been raised that varenicline may slightly increase cardiovascular events in people already at increased risk of those illnesses. Current evidence neither supports nor refutes such an association, but we await the findings of the CATS trial, which should establish whether or not this is a valid concern.

AUTHORS' CONCLUSIONS

Cytisine increases the chances of quitting, although absolute quit rates were modest in two recent trials. Varenicline at standard dose increased the chances of successful long-term smoking cessation between two- and three-fold compared with pharmacologically unassisted quit attempts. Lower dose regimens also conferred benefits for cessation, while reducing the incidence of adverse events. More participants quit successfully with varenicline than with bupropion or with NRT. Limited evidence suggests that varenicline may have a role to play in relapse prevention. The most frequently recorded adverse effect of varenicline is nausea, but mostly at mild to moderate levels and tending to subside over time. Early reports of possible links to suicidal ideation and behaviour have not been confirmed by current research.Future trials of cytisine may test extended regimens and more intensive behavioural support.

Varenicline and Adverse Cardiovascular Events: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Varenicline is an efficacious smoking‐cessation drug. However, previous meta‐analyses provide conflicting results regarding its cardiovascular safety. The publication of several new randomized controlled trials (RCTs) provides an opportunity to reassess this potential adverse drug reaction.

Methods and Results

We searched MEDLINE, EMBASE, and the Cochrane Library for RCTs that compare varenicline with placebo for smoking cessation. RCTs reporting cardiovascular serious adverse events and/or all‐cause mortality during the treatment period or within 30 days of treatment discontinuation were eligible for inclusion. Relative risks (RRs) with 95% CIs were generated by using DerSimonian–Laird random‐effects models. Thirty‐eight RCTs met our inclusion criteria (N=12 706). Events were rare in both varenicline (57/7213) and placebo (43/5493) arms. No difference was observed for cardiovascular serious adverse events when comparing varenicline with placebo (RR 1.03, 95% CI 0.72–1.49). Similar findings were obtained when examining cardiovascular (RR 1.04, 95% CI 0.57–1.89) and noncardiovascular patients (RR 1.03, 95% CI 0.64–1.64). Deaths were rare in both varenicline (11/7213) and placebo (9/5493) arms. Although 95% CIs were wide, pooling of all‐cause mortality found no difference between groups (RR 0.88, 95% CI 0.50–1.52), including when stratified by participants with (RR 1.24, 95% CI 0.40–3.83) and without (RR 0.77, 95% CI 0.40–1.48) cardiovascular disease.

Conclusions

We found no evidence that varenicline increases the rate of cardiovascular serious adverse events. Results were similar among those with and without cardiovascular disease. Given varenicline's efficacy as a smoking cessation drug and the long‐term cardiovascular benefits of cessation, it should continue to be prescribed for smoking cessation.

Varenicline for Smoking Cessation in Hospitalized Patients With Acute Coronary Syndrome

Background—

Less than one-third of smokers hospitalized with an acute coronary syndrome (ACS) remain abstinent following discharge. We assessed whether varenicline, begun in-hospital, is efficacious for smoking cessation following ACS.

Methods and Results—

We conducted a multi-center, double-blind, randomized, placebo-controlled trial in which smokers hospitalized with an ACS were randomized to varenicline or placebo for 12 weeks. All patients received low-intensity counseling. The primary end point was point-prevalence smoking abstinence assessed at 24 weeks by 7-day recall and biochemical validation using expired carbon monoxide. A total of 302 patients were randomized (mean age 55±9 years; 75% male; 56% ST-segment elevation myocardial infarction; 38% non-ST-segment elevation myocardial infarction; 6% unstable angina). Patients smoked a mean of 21±11 cigarettes/d at the time of hospitalization and had been smoking for a mean of 36±12 years. At 24 weeks, patients randomized to varenicline had significantly higher rates of smoking abstinence and reduction than patients randomized to placebo. Point-prevalence abstinence rates were 47.3% in the varenicline group and 32.5% in the placebo group ( P =0.012; number needed to treat=6.8). Continuous abstinence rates were 35.8% and 25.8%, respectively ( P =0.081; number needed to treat=10.0), and rates of reduction ≥50% in daily cigarette consumption were 67.4% and 55.6%, respectively ( P =0.05; number needed to treat=8.5). Adverse event rates within 30 days of study drug discontinuation were similar between groups (serious adverse events: varenicline 11.9%, placebo 11.3%; major adverse cardiovascular events: varenicline 4.0%, placebo 4.6%).

Conclusions—

Varenicline, initiated in-hospital following ACS, is efficacious for smoking cessation. Future studies are needed to establish safety in these patients.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00794573.

Big biomedical data and cardiovascular disease research: opportunities and challenges

Electronic health records (EHRs), data generated and collected during normal clinical care, are increasingly being linked and used for translational cardiovascular disease research. Electronic health record data can be structured (e.g. coded diagnoses) or unstructured (e.g. clinical notes) and increasingly encapsulate medical imaging, genomic and patient-generated information. Large-scale EHR linkages enable researchers to conduct high-resolution observational and interventional clinical research at an unprecedented scale. A significant amount of preparatory work and research, however, is required to identify, obtain, and transform raw EHR data into research-ready variables that can be statistically analysed. This study critically reviews the opportunities and challenges that EHR data present in the field of cardiovascular disease clinical research and provides a series of recommendations for advancing and facilitating EHR research.

Smoking cessation in Asians: focus on varenicline

Smoking is a modifiable risk factor for morbidity and mortality caused by cancer, cardiovascular diseases, respiratory diseases, and many other diseases. Given the large population size and high prevalence of smoking in Asia, successful smoking cessation could potentially prevent the large number of premature deaths in Asians. However, most dependent smokers cannot successfully quit smoking due to nicotine addiction, and they need professional help and smoking cessation therapies. Varenicline is a highly selective partial agonist for the nicotinic acetylcholine receptor α4β2 subtype, which is believed to be responsible for mediating the reinforcing properties of nicotine. This article is a narrative review, which summarizes the smoking cessation efficacy, side effects, and cost utilities of varenicline in Asians. From this review, we conclude that varenicline is an effective medication that could assist smoking cessation in the Asian populations. The adverse events of varenicline are tolerable, and the most common events were nausea and abnormal dreams. Both the efficacy and tolerance of varenicline in Asians are similar to that in Western populations. Considering the cost utilities, varenicline should be recommended for use in smoking cessation and be covered by medical insurance in most Asian countries.

Cost-effectiveness of retreatment with varenicline after failure with or relapse after initial treatment for smoking cessation

OBJECTIVES

A recent trial showed the clinical benefit of retreatment with varenicline in subjects failing on the initial treatment, or relapsing after initial success. The objective of this study was to evaluate the cost-effectiveness of retreatment with varenicline compared with other smoking cessation interventions.

METHODS

A published Markov model was adapted to compare one quit attempt of varenicline followed by retreatment to treatment/retreatment with nicotine replacement therapy (NRT), bupropion or placebo, and with only 1 quit attempt of varenicline. Efficacy was obtained from clinical trials. Incidence of smoking-related diseases was based on published data. Cost of therapies and complications was obtained from databases and literature.

RESULTS

For 1000 smokers willing to quit, varenicline retreatment saves 275,000€, 118,000€, 316,000€ and 237,000€ compared to NRT, bupropion, placebo, or one single varenicline quit attempt respectively at lifetime and from the healthcare payer perspective. The number of quality adjusted life years gained is 74, 63, 193 and 111 respectively. Sensitivity analyses showed the robustness of these findings.

CONCLUSION

This analysis suggests that in the long term, varenicline retreatment is a dominant intervention, meaning both greater health gains and greater costs saved, over other possible interventions and therefore should be considered as a standard option.

Varenicline and cardiovascular adverse events: a perspective review

Smoking is a leading preventable cause of mortality and morbidity. Varenicline, a first-line smoking cessation aid, is used widely to achieve successful quit rates in smokers. A number of studies and systematic reviews have evaluated the safety profile of the drug. To date, three systematic reviews by Singh and colleagues, Prochaska and Hilton, and Ware and colleagues, published between 2011 and 2013, have evaluated serious cardiovascular adverse events with varenicline use. Even though all three reviews demonstrated that serious cardiovascular adverse events were nominally more frequent in varenicline-treated patients when compared with placebo, a significantly increased event rate was found only in the review by Singh and colleagues. The three reviews included similar trials but differed in the evaluation of outcomes and performance of summary statistic computation. Though the evidence from the two most recent systematic reviews demonstrated that risk of serious cardiovascular events might not be increased with varenicline use, the US Food and Drug Administration has advised prescription with caution combined with close monitoring and education of patients until more conclusive evidence is available. Results of these reviews cannot be generalized to patients with unstable cardiac conditions.

Functional interactions of varenicline and nicotine with nAChR subtypes implicated in cardiovascular control

INTRODUCTION

It has been suggested that varenicline-induced activation of nicotinic acetylcholine receptors (nAChRs) could play a role in the cardiovascular (CV) safety of varenicline. However, since preclinical studies showed that therapeutic varenicline concentrations have no effect in models of CV function, this study examined in vitro profiles of varenicline and nicotine at nAChR subtypes possibly involved in CV control.

METHODS

Concentration-dependent functional effects of varenicline and nicotine at human α3β4, α3α5β4, α7, and α4β2 nAChRs expressed in oocytes were determined by electrophysiology. The proportion of nAChRs predicted to be activated and inhibited by concentrations of varenicline (1mg b.i.d.) and of nicotine in smokers was derived from activation-inhibition curves for each nAChR subtype.

RESULTS

Human varenicline and nicotine concentrations can desensitize and inhibit nAChRs but cause only low-level activation of α3β4, α4β2 (<2%), α7 (<0.05%), and α3α5β4 (<0.01%) nAChRs, which is consistent with literature data. Nicotine concentrations in smokers are predicted to inhibit larger fractions of α3β4 (48%) and α3α5β4 (10%) nAChRs than therapeutic varenicline concentrations (11% and 0.6%, respectively) and to inhibit comparable fractions of α4β2 nAChRs (42%-56%) and α7 nAChRs (16%) as varenicline.

CONCLUSIONS

Nicotine and varenicline concentrations in patients and smokers are predicted to cause minimal activation of ganglionic α3β4* nAChRs, while their functional profiles at α3β4, α3α5β4, α7, and α4β2 nAChRs cannot explain that substituting nicotine from tobacco with varenicline would cause CV adverse events in smokers who try to quit. Other pharmacological properties that could mediate varenicline-induced CV effects have not been identified.

Differential modulation of brain nicotinic acetylcholine receptor function by cytisine, varenicline, and two novel bispidine compounds: emergent properties of a hybrid molecule

Partial agonist therapies for the treatment of nicotine addiction and dependence depend on both agonistic and antagonistic effects of the ligands, and side effects associated with other nAChRs greatly limit the efficacy of nicotinic partial agonists. We evaluated the in vitro pharmacological properties of four partial agonists, two current smoking cessation drugs, varenicline and cytisine, and two novel bispidine compounds, BPC and BMSP, by using defined nAChR subtypes expressed in Xenopus laevis oocytes and human embryonic kidney 293 cells. Similar to varenicline and cytisine, BPC and BMSP are partial agonists of α4β2 nAChRs, although BMSP produced very little activation of these receptors. Unlike varenicline and cytisine, BPC and BMSP showed desired low activity. BPC produced mecamylamine-sensitive steady-state activation of α4* receptors that was not evident with BMSP. We evaluated the modulation of α4*- and α7-mediated responses in rat lateral geniculate nucleus (LGN) neurons and hippocampal stratum radiatum (SR) interneurons, respectively. The LGN neurons were sensitive to a very low concentration of varenicline, and the SR interneuron responses were also sensitive to varenicline at a submicromolar concentration. Although 300 nM BPC strongly inhibited the ACh-evoked responses of LGN neurons, it did not inhibit the α7 currents of SR interneurons. Similar results were observed with 300 nM BMSP. Additionally, the bispidine compounds were efficacious in the mouse tail suspension test, demonstrating that they affect receptors in the brain when delivered systemically. Our data indicate that BPC and BMSP are promising α4β2* partial agonists for pharmacotherapeutics.