Smoking is the most common preventable cause of premature death in the world, and cardiovascular disease (CVD) is the most common cause of death, whether secondary to smoking or not. About half of all smokers try to quit each year, many of whom use nicotine-replacement therapy (NRT), or the drugs bupropion or varenicline (Zyban or Chantix, respectively). Researchers from Stanford University (Edward J. Mills, PhD, MSc) and two Canadian centers performed a meta-analysis with the goal of determining if smokers on NRTs (patches, gums, inhalers) or drugs to help them quit were at elevated risk of CVD, as compared to those on a placebo.
The analysis, published in the AHA s journal, Circulation, evaluated 63 trials involving 30,508 people. The results showed that the use of NRTs was associated with a significantly increased risk almost double, in fact for all cardiovascular events compared with placebo. However, sensitivity analysis revealed that the treatment effect among NRT users was largely driven by less dangerous CVD events, including rapid heartbeat (tachycardia) and occasional irregular heartbeat (arrhythmia). These events most often occurred in studies with the longest follow-up periods, and occurred more often among NRT users who also continued smoking.
The study authors gave this assessment: "Given the current findings of low risk of serious CVD events attributed to smoking cessation pharmacotherapies, combined with the well-established CVD and mortality risks of continued smoking, the benefits of use would seem to outweigh the risks: however, further study is needed, particularly investigation of the use of cessation medications with smokers hospitalized for ST-elevation MI (myocardial infarction, heart attack).
ACSH s Dr. Gilbert Ross had this perspective: An editorial accompanying this study, written by well-known USC epidemiologist, Dr. Jon Samet, noted the history of the success rates of these products thusly:
Each of these medications, used in conjunction with appropriate counseling and support, increases the likelihood of sustained cessation; in a 2013 meta-analysis, bupropion and NRT approximately doubled quit rates while varenicline had a significantly higher success rate, almost three-fold that of placebo. Each of these agents has also been linked to diverse adverse effects, including recent and controversial concerns for cardiovascular disease (CVD) risk.
What Dr. Samet neglects to tell us is that, given the placebo quit rates of less than 5 percent, these FDA-approved cessation therapies have a success rate of between 10 and 15 percent: they don t work very well at all to help addicted smokers quit. And neither the study nor the editorial took any pains to discuss electronic cigarettes in this context.
So the take-home message seems to be, while these cessation aids fail almost 9 times out of 10, at least they don t do too much harm. Not quite a ringing endorsement, but they re the best we have. Or are they?