The new clinical program builds on a research biobank and genome-sequencing initiative called MyCode that Geisinger started in 2007 to collect and analyze its patients' DNA. That effort has enrolled more than 200,000 people.
Like MyCode, the new clinical program will be based on "whole exome" sequencing, analyzing the roughly 1 percent of the genome that provides instructions for making proteins, where most known disease-causing mutations occur.
Using this analysis, clinicians could tell Geisinger patients whether they have a genetic variant associated with Lynch syndrome, for example, which leads to an increased risk of cancer of the colon and some other cancers. Or doctors could offer guidance to patients found to have an increased risk for familial hypercholesterolemia, which can result in high cholesterol levels and heart disease at a young age.
Still other patients who undergo the exome sequencing might learn they have an increased susceptibility to malignant hyperthermia, because of a gene variant that causes a severe reaction to certain medications used during anesthesia; the reaction can be fatal.
Geisinger spokesperson Wendy Wilson says that what the company plans is very different from direct-to-consumer services like 23andMe — which tests customers' saliva to determine their genetic risk for several diseases and traits, only some of which are medically actionable, and makes the results available in an online report.
"Geisinger is prescribing DNA sequencing to patients and putting DNA results in electronic health records and actually creating an action plan," Wilson says. "We are preventing disease from happening."
Geisinger says its program will work like this: Samples of a patient's blood or spit will be used to get a DNA sample. After analysis, the results will be sent to the patient's primary care doctor.
The doctor will then take a 30-minute online continuing education tutorial to review genetic testing and get more information on whatever specific susceptibilities have turned up in that patient's results.
After that, the patient will be informed and invited to meet with the primary care provider, along with a genetic counselor if desired. At that point the doctor and patient can discuss treatment and prevention options, including any particular lifestyle changes that might reduce the risk of developing the disease or condition.
About 3.5 percent of the people who have already been tested through Geisinger's research program had a genetic variant that could result in a medical problem for which clinicians can recommend helpful steps to influence their health, Feinberg says.
In the clinical program, only actionable mutations will be communicated to patients. The health care team, for example, won't inform patients if they have a variant of the APOE gene that somewhat increases their risk for getting Alzheimer's disease, because that information wouldn't change anything about their medical treatment. (Geisinger is developing a policy for how to handle these results if patients ask for them.)
Insurance companies typically don't cover DNA sequencing and do limit a patient's coverage for adult genetic tests for specific mutations, such as those related to the breast cancer susceptibility genes BRCA1 or BRCA2, unless the patient has a family history of the condition or other indications they're at high risk. For each of the patients it tests, Geisinger will absorb the estimated $300 to $500 testing cost.
"Most of the medical spending in America is done after people have gotten sick," says Feinberg. "We think this will decrease spending on a lot of care."
But some clinicians and academics outside Geisinger aren't so sure. One of them is Dr. H. Gilbert Welch, a professor at the Dartmouth Institute for Health Policy and Clinical Practice who has written books about the hazards of overdiagnosis and overscreening, including, Less Medicine, More Health.
He credits Geisinger with carefully targeting the mutations in which it looks for actionable mutations, instead of taking an all-encompassing approach. And he acknowledges that for some conditions, like Lynch syndrome, people with certain genetic mutations would benefit from being followed closely. But he questions the value of DNA sequencing to identify some other susceptibilities, such as some of the genetic variants related to cardiovascular disease.
"What are we really going to do differently for those patients?" he asks. "We should all be concerned about heart disease. We should all exercise; we should eat real food."
Welch says he's also concerned about the cascading effect of expensive and potentially harmful medical treatment when a genetic risk is identified.
"Doctors will feel the pressure to do something — start a medication, order a test, make a referral," he warns. "You have to be careful. Bad things happen."
Other clinicians question primary care physicians' comfort with and time for incorporating DNA sequencing into their practices.
A survey published this month in the journal Health Affairs queried nearly 500 primary care providers in the New York City area and found that, in the past year, only a third of them had ordered a genetic test, given patients a genetic test result or referred someone for genetic counseling.
Only a quarter of the survey respondents said they felt prepared to work with patients who had genetic testing for common diseases or were at high risk for genetic conditions. Just 14 percent reported they were confident they could interpret genetic test results.
"Even though they had training, they felt unprepared to incorporate genomics into their practice," says Dr. Carol Horowitz, an internist and professor at the Icahn School of Medicine at Mount Sinai in New York, who co-authored the study.
A busy primary care practitioner herself, Horowitz questions the feasibility of adding genomic medicine to regular office visits.
"Geisinger is a very well-resourced health system and they've made a decision to incorporate that into their practices," she says, adding that in Harlem, where she practices, it could be a daunting challenge. "Our plates are already overflowing, and now you're going to dump a lot more on our plate."