Blood Test Can Determine Best Way to Quit Smoking

A blood test may determine the most effective way for individual smokers to quit, according to research published in Lancet Respiratory Medicine.

Researchers from the University of Pennsylvania Perelman School of Medicine genetically tested 1,246 smoker participants for a biomarker called nicotine metabolite ratio (NMR), which predicts response to nicotine patch or varenicline for smoking cessation. There were 662 slow metabolizers of nicotine included in the study and 584 normal metabolizers. The patients were recruited for the placebo controlled trial which took place from November 16, 2010 to September 12, 2014 across 4 sites. The patients were randomly assigned to receive 11 weeks of placebo (placebo pill plus placebo patch), nicotine patch (active patch plus placebo pill), or varenicline (active pill plus placebo patch), plus behavioral counseling. Participants were monitored for follow up for 12 months after the target quit date, and cessation was biochemically verified after 7 days.

The researchers believed slow metabolizers would likely benefit from the nicotine patch, while normal metabolizers would more likely be successful in smoking cessation with the varenicline pill.

“Matching a treatment choice based on the rate at which smokers metabolize nicotine could be a viable strategy to help guide choices for smokers and ultimately improve quit rates,” lead author Caryn Lerman, PhD, a professor of Psychiatry and director of the Center for Interdisciplinary Research on Nicotine Addiction, said in a press release.

At the end of the treatment, the varenicline treatment was more efficacious then nicotine patches in normal metabolizers, but not in slow metabolizers, as expected. About 40 percent of the normal metabolizers on varenicline were still avoiding smoking at the end of the 12 month observation period, compared to just 22 percent of the patch cohort. The slow metabolizers group also experienced more overall side effects. The cessation rates also decreased in both groups at the 6 and 12 month marks, but the ratios for normal and slow metabolizers on the patch and varenicline remained.

Prior smoking cessation researchers indicated that if a person is tobacco free after 7 days, they will likely remain that way for 6 months, if not longer. Therefore, being tobacco free for just 1 week is highly indicative of long term cessation success.

“These findings not only support the use of the nicotine metabolite ratio as a biomarker to guide treatment choices,” Lerman continued, “but also underscore the notion that tobacco dependence is a heterogeneous condition and that smoking cessation treatments are not equally effective for all smokers.”