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Survey Explores Provider Attitudes on Who Should Act on Patients' PGx Testing Results


NEW YORK (GenomeWeb) – A survey at Vanderbilt University found that healthcare providers ordering pharmacogenomic testing don't need convincing of its usefulness in patient care.

But the study, published this week in The Phamacogenomics Journal, also showed that clinicians who had taken part in Vanderbilt's preemptive PGx testing program could not agree on who should be responsible for acting on the results to personalize care for patients.

"Assigning clinical responsibility is clearly an issue with multiplex testing," Josh Peterson, lead study author and an assistant professor of biomedical informatics at Vanderbilt, told GenomeWeb. "That's the bottom line of the paper, and it has to be explored further."

A preemptive testing scenario is one where patients get tested for genetic variants associated with response to a drug they might need in the future and the results are stored in electronic medical records (EMR). Then, if a physician goes to prescribe this drug in the future, the EMR alerts the doctor of pertinent genomic data that might impact the patient's ability to metabolize the drug or increase the risk for adverse events. Based on this information the doctor can take action, such as change the drug dose or prescribe a different treatment.

In practice, this path from the physician getting alerted to taking action isn't so straightforward. Patients see multiple healthcare professionals — primary care providers, specialists, and nurses — who all might have reason to consider PGx test results throughout the continuum of a patient's care. Moreover, patients don't stay in one place. What happens when new, clinically pertinent PGx information emerges for a patient after he or she has left the healthcare system?

This challenge of managing medical information flow between healthcare systems and getting the information to the patient when it's needed isn't just a problem for genomics data. But as more genomic testing is done and more variants are applied to patient care, it does stand to exacerbate the problem, according to Peterson, by providing "potentially useful information over a very long time."

Vanderbilt has been thinking about how to manage this complexity in the five years running its preemptive testing program, called Pharmacogenomic Resource for Enhanced Decisions in Care and Treatment (PREDICT). Researchers have tested close to 15,000 patient samples in that time for variations in several dozen genes, but PREDICT is currently reporting markers for only four PGx indications in patients' EMRs: testing for CYP2C19 variants for response to the antiplatelet drug Plavix (clopidogrel); CYP2C9 and VKORC1 polymorphisms for response to the anticoagulant warfarin; TPMT variants for response to thiopurine agents; and CYP3A5 alleles for response to the immunosuppressive drug tacrolimus.

"We think of PREDICT as a series of interventions," Peterson said. Providers can encounter patients' PGx test results in a variety of ways, depending on the workflow required for a specific clinical situation. They might receive an alert or see it in the lab reports section of the EMR, or as in the case of CYP2C19 variants related to clopidogrel, they might get a call from the pharmacist.

Also, a single PGx result could potentially impact many different aspects of a patient's care over time, Peterson pointed out. "You're getting it for one of those reasons, but the [provider] getting the result isn't simultaneously thinking about all the reasons the patient could use this information over their lifetime," he said.

The latest study was performed from the end of 2013 to early 2014, and surveyed healthcare providers who requested or received results from the PGx panel for primary care or cardiovascular patient populations. Of the approximately 80 clinicians who returned surveys, 63 percent had ordered or recommended a test in the last six months; 95 percent had familiarity with the PGx program; and about the same proportion had prescribed at least one of the drugs (clopidogrel, warfarin, and simvastatin) that would have been impacted by the PGx testing program at the time.

In the survey, nurses, fellows, and physicians practicing in cardiology and non-cardiology settings were asked to respond to two hypothetical scenarios. In one, a patient receives PGx testing after undergoing a stent procedure and is found to be a poor metabolizer of clopidogrel. In the second, six months after the stent procedure, the PGx program reports that the patient has a variant that increases the risk of bleeding at standard or high doses of warfarin. However, by this time, the patient is getting care in his hometown, and is no longer at Vanderbilt. Given these scenarios, the survey explored clinicians' attitudes about who should be individually notified about the PGx result beyond including it in the EMR, and who they think is responsible for acting on the result.

In response to the first scenario regarding clopidogrel, non-cardiologists most frequently said that the provider who prescribed the drug or the specialist treating the condition affected by the results should be informed. Meanwhile, most cardiologists indicated that the specialist treating the patient for the specific medical condition should be informed of these results. This suggests that many cardiologists were assuming it was their own responsibility to figure out the next steps for a patient based on the results.

"But there's often two cardiologists involved in a patient's care, the general and the interventional cardiologist," Peterson noted. "So, even between those two physicians there may be some dilemmas about who needs to take responsibility for this kind of data."

There was less agreement with the second scenario where the patient was receiving care outside of Vanderbilt's system. Clinicians most frequently indicated that PREDICT program staff should take responsibility for contacting outside providers, and many thought that the doctor at Vanderbilt who had ordered the test should follow-up.

The second scenario presented more of a challenge for the respondents, according to Peterson. "Not only isn't this patient at Vanderbilt, this patient isn't in our health system," he said, noting this is a fairly common situation for patients receiving care at tertiary academic medical centers.

This "responsibility" to constantly monitor for new PGx results stands to become an acute problem once more patients start to receive such testing and as more variants are reported in the EMR. "That's a really tall order for stressed specialists or primary care physicians," Peterson said.

Currently, the PREDICT program does have a patient portal that can be used to inform people, even those getting care outside the system, about new PGx information. This is a good start, Peterson said, but it depends on patients actually logging in to the portal. It might also be useful, he noted, to have a mechanism through which non-Vanderbilt providers would be able to access this information.

"It's much easier to store and design the system in a passive way," Peterson said. But his group is trying to figure out how active the information push needs to be when useful data emerges. In the survey, most clinicians indicated they wanted to be informed of PGx results as soon as they were available in the EMR, but they also wanted to be notified in other ways. For example, many wanted PREDICT staff to notify them through electronic clinical messages, while some preferred to get decision support through e-prescribing or via phone calls.

Vanderbilt is figuring this out as it gets ready to launch a sequencing service for PGx and disease risk assessment as part of the third phase of NIH’s Electronic Medical Records and Genomics Network. For example, Peterson noted that it won't be enough to place disease risk information, like a patient's BRCA mutation status, simply in the lab reports section, where it's likely to be buried after a few years. So, Vanderbilt is planning to report genomic markers for disease risk prominently in the EMR and set it apart from other lab test information. Additionally, Vanderbilt will have consultation services for physicians and decision support alerts in the EMR to ensure the right eyes are seeing important information.

One of the encouraging findings of this study was that even though the evidence base for some of genetic markers may change over time (e.g. markers associated with clopidogrel and warfarin response), clinicians seem to be keeping track of the literature. The surveyed providers ranked the strength of evidence backing the gene-drug interactions and patients' out-of-pocket costs as their most important considerations when deciding to order testing.

They further indicated that specialty society guidelines and the published literature most influenced their perceptions of which PGx tests were clinically useful. Based on the evidence for a drug-gene interaction, clinicians' attitudes might change over time about which PGx tests to use, "but that's a good thing," Peterson said. "That means they're paying attention to the evidence."