Fear factor in DTC gene tests: not so scary after all?

Direct-to-consumer genetic testing is controversial in part because many medical professionals and policymakers fear that it will prompt inflated perceptions of risk in patients poorly equipped to interpret test results. A small study suggests that, at least for those administered the test through a clinical setting, that concern may be overblown.

Researchers assigned 150 participants, recruited through a major medical center's outpatient clinic, to intervention and control groups. The intervention group got a mail-in saliva sample collection kit (of unproven efficacy), made by Navigenics, Inc., that tested for genomic risk factors in 12 diseases, including abdominal aneurysm, atrial fibrillation, breast cancer, celiac disease, colon cancer, type 2 diabetes mellitus, Graves disease, heart attack, lung cancer, obesity, osteoarthritis and prostate cancer. They got their results a week before a scheduled doctor's visit, and their docs were given their test results to go over with them. Physicians were not provided any special training in interpreting the risk profiles, and patients were just told they had the option of discussing the results with their doctors. Patients in the control group received only standard care—physical, medical and family history review, age-appropriate screenings, shots, etc.

For a little more than half of all conditions, perceived risk was initially high, and particularly high for four conditions—abdominal aneurysm, Graves disease, obesity and osteoarthritis. However, a one-year follow-up survey found no appreciable difference between the intervention and control groups. Surprisingly, levels of worry about prostate cancer were actually lower for those receiving the test.

That suggests, authors said, “that receiving predictive genomic risk information influences patients' perceptions of risk and levels of worry for developing a variety of conditions, but does so in different ways and to varying degrees for different conditions.” Discussing those results with a trusted physician may account for the “relatively modest impact.”

That's important because, as the study, which ran in the October edition of Mayo Clinic Proceedings, puts it, “Health information can be managed in both positive and negative ways, especially in the context of genomic risk information. For example, if an individual is told that he or she is at increased genetic risk of developing heart disease, that person might decide that engaging in risk-reducing activities such as weight loss or exercise would have no bearing on his or her chance of developing the disease.” Or they might besiege their doctors demanding more expensive tests and procedures for a disease they don't have.