About a quarter of the survey respondents reported sharing their tests results with their doctors, and this subset did make healthier exercise and diet choices than did the group as a whole. However, it’s unclear if this group was more motivated to get healthy to start with, prompting them to visit their physicians, or if the doctor’s consultation triggered the changes.
The findings show how important it is to have physicians involved in the process, says Vance Vanier, the president of Navigenics. Unlike other tests, the one from Navigenics is available only through physicians or corporate-wellness programs, rather than directly online. However, most physicians are ill equipped to deal with the results of genetic testing. “Surveys show 90 percent of physicians don’t feel comfortable using genetic data to guide therapy,” says Topol.
Only 10 percent of respondents availed themselves of free genetic counseling, which was offered together with the test. Unlike general practitioners, genetic counselors are specially trained to help patients interpret and use genetic tests. Vanier says Navigenics has changed its approach to counseling as a result of these findings. The company now actively follows up with users to offer counseling, rather than waiting for them to call in.
Given the state of the health-care system, one of the greatest concerns about direct-to-consumer tests has been that they would tax the system. However, people did not report undergoing more medical procedures as a result of the tests, a finding that is confirmed by the Coriell study. “That suggests that concerns about overuse of the medical system may be premature,” says Erynn Gordon, director of genetic counseling at Coriell. “I don’t think anyone has enough data at this point to say the question can be put to rest. But there’s a lot more concern expressed than evidence to support that it’s a problem.”
People predicted to be at higher risk of certain cancers did report higher intent to get follow-up screening tests, such as colonoscopies and mammograms. However, it’s still unclear whether they will follow through on their intentions. Topol says his team continues to follow participants and will try to answer this question.
Both Topol’s team and the Coriell group now plan to look at the effects of pharmacogenetics information, genetic mutations that predict how well certain drugs, such as Plavix, will work in an individual, or how susceptible that person will be to side effects. Because this information has more obvious consequences—physicians may choose a different drug or prescribe lower doses—these tests may have a greater impact than ones predicting genetic risk of disease. “People ought to take that information more seriously now,” says Christman. “For example, Plavix, the second most prescribed drug in the world, doesn’t work for a quarter of the people who take it.”