Risk of serious adverse cardiovascular events associated with varenicline: a systematic review and meta-analysis

Pharmacologic agents for tobacco dependence treatment: 2011 update

Tobacco use remains the most important worldwide cause of preventable death due mainly to cancer, cardiovascular disease, and chronic lung disease. If the current tobacco pandemic continues for another 20 years, the annual global tobacco-attributable mortality will exceed 8 million. In the US and many European countries, public health and tobacco control efforts combined with effective tobacco dependence treatment using combined behavioral treatment and pharmacotherapy have contributed significantly to steadily declining rates of tobacco use. Subsequent declines in cardiovascular disease and lung cancer death rates are directly attributable to these lower rates of tobacco use. Despite smoking bans, health warnings and effective pharmacotherapy, one in five Americans continue to smoke. Continued research in tobacco dependence treatment has resulted in newer and more effective pharmacotherapy. In this review, we provide a current update of pharmacologic agents for tobacco dependence treatment and a discussion of recent controversy regarding adverse effects of some these medications.

Risk of cardiovascular serious adverse events associated with varenicline use for tobacco cessation: systematic review and meta-analysis

OBJECTIVE

To examine the risk of treatment emergent, cardiovascular serious adverse events associated with varenicline use for tobacco cessation.

DESIGN

Meta-analysis comparing study effects using four summary estimates.

DATA SOURCES

Medline, Cochrane Library, online clinical trials registries, and reference lists of identified articles.

REVIEW METHODS

We included randomised controlled trials of current tobacco users of adult age comparing use of varenicline with an inactive control and reporting adverse events. We defined treatment emergent, cardiovascular serious adverse events as occurring during drug treatment or within 30 days of discontinuation, and included any ischaemic or arrhythmic adverse cardiovascular event (myocardial infarction, unstable angina, coronary revascularisation, coronary artery disease, arrhythmias, transient ischaemic attacks, stroke, sudden death or cardiovascular related death, or congestive heart failure).

RESULTS

We identified 22 trials; all were double blinded and placebo controlled; two included participants with active cardiovascular disease and 11 enrolled participants with a history of cardiovascular disease. Rates of treatment emergent, cardiovascular serious adverse events were 0.63% (34/5431) in the varenicline groups and 0.47% (18/3801) in the placebo groups. The summary estimate for the risk difference, 0.27% (95% confidence interval -0.10 to 0.63; P = 0.15), based on all 22 trials, was neither clinically nor statistically significant. For comparison, the relative risk (1.40, 0.82 to 2.39; P = 0.22), Mantel-Haenszel odds ratio (1.41, 0.82 to 2.42; P = 0.22), and Peto odds ratio (1.58, 0.90 to 2.76; P = 0.11), all based on 14 trials with at least one event, also indicated a non-significant difference between varenicline and placebo groups.

CONCLUSIONS

This meta--analysis--which included all trials published to date, focused on events occurring during drug exposure, and analysed findings using four summary estimates-found no significant increase in cardiovascular serious adverse events associated with varenicline use. For rare outcomes, summary estimates based on absolute effects are recommended and estimates based on the Peto odds ratio should be avoided.