The British Medical Journal has published the results of a study that aimed to assess any association between varenicline use and cardiovascular events.
Post marketing surveillance has raised concerns that there may be cardiovascular risks associated with the use of varenicline in stopping smoking. A retrospective cohort analysis of a Danish medical database was use to compare the rates of cardiovascular events in individuals prescribed varenicline as compared to those prescribed buproprion.
The study accessed data for 4,781,228 individuals and identified 92,540 people who had been prescribed either varenicline or bupropion. A total of 35,852 patients were reviewed after being matched in a 1:1 ratio for each drug. The primary outcomes were acute coronary syndrome, ischaemic stroke and cardiovascular death analysed individually and as a composite of any major cardiovascular event.
There were 57 major cardiovascular events in those prescribed varenicline (6.9 cases per 1,000 person years) compared to 60 events in those prescribed buproprion (7.1 cases per 1,000 person years). The hazard ratio was 0.96 (95% confidence interval 0.67 to 1.39). There were no differences in rates of the individual component outcomes.
An accompanying editorial notes that the use of an active comparator limits the usefulness of this study. The only conclusion that can be drawn is the varenicline poses the same level of cardiovascular risk as buproprion. The editorial states, "This may not help us determine whether varenicline should be prescribed to patients at higher risk of cardiovascular disease, or to determine whether myocardial infarction in a patient who has taken varenicline is causally related to the drug".
Action: Clinicians should be aware of this study. Although, at first glance, this study is reassuring perhaps more research is necessary and continued post marketing surveillance is vital.
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