WASHINGTON Few physicians feel prepared to interpret findings from direct-to-consumer genetic tests and incorporate the results into clinical practice, according to speakers at a National Academy of Sciences workshop on DTC genetic testing.
Surveys and anecdotal accounts discussed at the meeting cast doubt on the idea that physicians will be able to help consumers decide what to do about any health risks identified by DTC genetic tests.
"There's a lot of confusion between these services and medical care," Dr. Patricia Ganz said. DTC companies may say that test results are for educational and research purposes only, and cannot be used for diagnostic purposes because the tests have not been validated for clinical use, but the results are "in fact being very much treated as medical information."
The difference between how the tests are marketed and what's feasible in clinical practice point to a "number of risks to the clinical encounter," said Dr. Ganz, professor of health services and medicine at the University of California, Los Angeles. Possible problems include a demand for screening tests that have no proven clinical value and the perception that a physician is unsympathetic or lacking in knowledge when reviewing a patient's DTC genetic test report.
Some physicians currently use genetic tests with known clinical value, such as tests for blood disorders or prenatal risk assessment, Dr. Ganz said. But many physicians have little need for test results about cancer predisposition or other genetic syndromes, and are even less likely to be prepared to interpret DTC genetic test reports derived from case-control association studies and genome-wide association studies.
Published reports indicate that physicians obtain most of their information about DTC genetic testing through the media, Katrina Goddard, Ph.D., of the Kaiser Permanente Center for Health Research, Portland, Ore., said at the workshop.
An online physician survey, called DocStyles, included 1,250 respondents (response rate 61%) in 2006 and 1,880 (response rate 22%) in 2008. More than 60% of the respondents reported getting information about DTC testing from the media, and less than 30% said they obtain information about such testing from other sources (Genet. Med. 2007;9:510-7; Genet. Med. 2009;11:595).
The questions in each survey were "not completely comparable" between time periods. The 2006 survey questions focused on nutrigenomic tests, while the 2008 questions centered on genetic tests for complex diseases that used data from genome-wide association studies. Of the surveyed physicians, 50% were aware of the nutrigenomic tests and 42% were aware of the tests for complex diseases.
In the same reports, national surveys of consumers showed that 14% were aware of the tests covered in the 2006 survey, and 22% were aware of the tests in the 2008 survey, but less than 1% used the tests.
Nearly half of the physicians who said they were aware of DTC genetic tests said they had patients with questions about the tests. About 15% of these physicians had one or more patients who brought in their test results for discussion. Some aspect of the patient's care changed in 75% of these encounters, according to the survey.
At the workshop, Joseph McInerney, executive director of the National Coalition for Health Professional Education in Genetics, said that individuals and families with genetic conditions also do not appear confident about their provider's knowledge of genetics.
In a survey of 5,915 respondents conducted by the Genetic Alliance, an advocacy group, more than 30% rated as poor their provider's understanding of genetics and ability to deal with genetics-related management issues (Genet. Med. 2007;9:259-67).
Physicians who search for resources to help in interpreting DTC test results are likely to turn to point-of-care clinical decision tools. But current versions of these tools often lack relevant information and are inefficient to use, Mr. McInerney said.
None of the speakers disclosed conflicts of interest with DTC genetic testing companies.
Families with genetic conditions do not appear confident about their provider's knowledge of genetics.
Source Mr. McInerney
Only two U.S. medical schools have integrated medical genetics into their curricula for all 4 years, which suggests there are not enough professors and instructors sufficiently well trained in genetics to connect basic and clinical science during training, Mr. McInerney said at the workshop.
"There is a perception among many health care providers that genetics is still quite circumscribed by traditional, Mendelian, rare genetic disease and chromosomal anomalies," he said. "Genetics has clearly moved beyond that into the realm of common, complex disease."
He noted that a 2005 survey of 149 U.S. and Canadian course directors in medical genetics or curricular deans in medical schools found that 77% of the schools taught medical genetics in the first year, but only 47% incorporated it into the third or fourth year (Acad. Med. 2007;82:441-5). General concepts accounted for 86% of the instruction in genetics, with little focus on practical applications. Medical genetics was taught as a stand-alone course (46%) or as part of another course (54%).