ADVERTISEMENT

Doctors dispute study

If you've ever tried to quit smoking, you know how difficult it is. Nicotine is so addictive that smokers often must try multiple smoking-cessation aids and combinations of aids before they're able to break the habit - a critical step for people with heart disease.
Many people have been successful with a drug called varenicline (Chantix), which acts directly on the brain to interfere with nicotine dependence. Doctors recently became concerned when an analysis of existing studies on varenicline published in the Canadian Medical Association Journal concluded that the drug posed a significant risk of serious cardiovascular events.
Dr. Nancy Rigotti, director of the Tobacco Research and Treatment Center at Massachusetts General Hospital and a professor at Harvard Medical School, is among the many physicians who questioned this conclusion. Rigotti and her colleagues conducted the largest study on varenicline to date, which was published in Circulation in 2010. The study involved more than 700 smokers with stable cardiovascular disease, who took the drug for 12 weeks. One year later, the research team found no increased rate of heart attack or death from cardiovascular or other cause.
"We found no changes in blood pressure or heart rate to suggest there was a mechanism that would cause cardiovascular events," says Rigotti.
How could two researchers reach such different conclusions? The answer may lie in the method used to analyze the data. A third researcher who questioned the CMAJ study repeated the analysis using a different statistical method and found nothing to be concerned about.
But varenicline is a drug, and any possible risks incurred by using it must be balanced against the known benefits of quitting smoking. Here, the benefits are clear.
"Of all things we consider essential after a heart attack, smoking cessation is as important - or more important - than anything else. If you quit smoking, your risk of cardiac death will drop 37 percent," says Rigotti.

- Harvard Health Letters