Regulatory agencies in UK and US have yet to address dangers inherent in customer misunderstanding of DTC medical laboratory genetic test results
Direct-to-consumer (DTC) medical laboratory genetic tests are gaining popularity across the globe. But recent research out of the United Kingdom questions the reliability of these tests. The study, according to The Guardian, found that “Over the counter genetic tests in the UK that assess the risk of cancer or heart problems fail to identify 89% of those in danger of getting killer diseases.”
According the PGS website, “each PGS in the catalog is consistently annotated with relevant metadata; including scoring files (variants, effect alleles/weights), annotations of how the PGS was developed and applied, and evaluations of their predictive performance.”
However, the researchers told The Guardian, “Polygenic risk scores performed poorly in population screening, individual risk prediction, and population risk stratification. Strong claims about the effect of polygenic risk scores on healthcare seem to be disproportionate to their performance.”
“Strong claims have been made about the potential of polygenic risk scores in medicine, but our study shows that this is not justified,” Aroon Hingorani, PhD (above), Professor of Genetic Epidemiology at UCL and lead author of the study, told The Guardian. “We found that, when held to the same standards as employed for other tests in medicine, polygenic risk scores performed poorly for prediction and screening across a range of common diseases.” Consumer misunderstanding of DTC medical laboratory genetic tests is a real danger. (Photo copyright: University College London.)
Polygenic Scores Not Beneficial to Cancer Screening
To complete their study, the UCL researchers compared PGS genetic risk data to conventional clinical laboratory testing methods and discovered some troubling results. They include:
On average, only 11% of individuals who developed a disease had been identified by the tests.
A 5% false positive rate where people were informed that they would get a disease within 10 years but did not.
PGS only identified 10% of people who later developed breast cancer.
The researchers state in their BMJ Medicine paper that polygenic risk scores are not the same as testing for certain gene mutations, which could be critical in screening for some cancers. They also wrote that discovering genetic variants associated with the risk for disease is still crucial for drug development.
“It has been suggested that polygenic risk scores could be introduced early on to help prevent breast cancer and heart disease but, in the examples we looked at, we found that the scores contributed little, if any, health benefit while adding cost and complexity,” research physician and epidemiologist Sir Nicholas Wald, FRS, FRCP, FMedSci, Professor of Preventive Medicine at UCL Institute of Health Informatics and co-author of the study, told the Jersey Evening Post.
“Our results build on evidence that indicates that polygenic risk scores do not have a role in public health screening programs,” Wald added.
“This research study rightly highlights that for many health conditions genetic risk scores alone may have limited usefulness, because other factors such as deprivation, lifestyles, and environment are also important,” clinical epidemiologist Raghib Ali, MD, CEO, Chief Investigator and Chief Medical Officer, Our Future Health UK, told The Guardian.
Our Future Health is a collaboration between public, non-profit, and private sectors to create the UK’s largest health research program. The researchers in this endeavor intend to recruit over five million volunteers and use polygenic risk scores to develop innovative ways to prevent, detect, and treat disease. This program is funded by the UK’s National Health System (NHS).
“[Our] research program will be developing integrated risk scores that will take in all the important risk factors,” Ali explained. “We hope these integrated risk scores can identify people more likely to develop diseases, but this is a relatively new area of science and there are still unanswered questions around it.”
Danger of Misunderstanding DTC Genetic Tests
Here in the US, there have been news stories in recent years about the unreliability of certain genetic tests. Dark Daily covered these stories in previous ebriefs. News stories about the unreliability of genetic tests, particularly those marketed directly to consumers, reveal the problems that existing regulatory schemes have yet to address.
In “Consumer Reports Identifies ‘Potential Pitfalls’ of Direct-to-Consumer Genetic Tests,” we covered CR’s findings that though clinical laboratory and pathology professionals understand the difference between a doctor-ordered genetic health risk (GHR) test and a direct-to-consumer (DTC) genetic test, the typical genetic test customer may not. And that, misunderstanding the results of a DTC at-home genetic test can lead to confusion, loss of privacy, and potential harm.
Scientific American also covered the dangers of DTC testing in “The Problem with Direct-to-Consumer Genetic Tests,” in which the author notes that “despite caveats in ads and on packages, users can fail to understand their limitations,” and that “consumer-grade products are easily misconstrued as appropriate medical tests and create false reassurances in patients who could be at legitimate risk.”
Most clinical laboratory managers and pathologists are probably not surprised that the research performed at UCL shows that there are still issues surrounding genetic tests, particularly those marketed directly to consumers. While direct-to-consumer DNA tests can have some benefits, at this time, they are not always the best option for individuals seeking information about their personal risk for hereditary diseases.
The focus of the ongoing GenoVA study is to “determine the clinical effectiveness of polygenic risk score testing among patients at high genetic risk for at least one of six diseases measured by time-to-diagnosis of prevalent or incident disease over 24 months,” according to the National Institutes of Health.
The scientists used data obtained from 36,423 patients enrolled in the Mass General Brigham Biobank. The six diseases they researched were:
The polygenic scores were then tested among 227 healthy adult patients to determine their risk for the six diseases. The researchers found that:
11% of the patients had a high-risk score for atrial fibrillation,
7% for coronary artery disease,
8% for diabetes, and
6% for colorectal cancer.
Among the subjects used for the study:
15% of the men in the study had a high-risk score for prostate cancer, and
13% of the women in the study had a high score for breast cancer.
The researchers concluded that the implementation of PRS may help improve disease prevention and management and give doctor’s a way to assess a patient’s risk for these conditions. They published their findings in the journal Nature Medicine, titled, “Development of a Clinical Polygenic Risk Score Assay and Reporting Workflow.”
“We have shown that [medical] laboratory assay development and PRS reporting to patients and physicians are feasible … As the performance of PRS continues to improve—particularly for individuals of underrepresented ancestry groups—the implementation processes we describe can serve as generalizable models for laboratories and health systems looking to realize the potential of PRS for improved patient health,” the researchers wrote.
Using PRS in Clinical Decision Support
Polygenetic risk scores examine multiple genetic markers for risk of certain diseases. A calculation based on hundreds or thousands of these genetic markers could help doctors and patients make personalized treatment decisions, a core tenet of precision medicine.
“As a primary care physician myself, I knew that busy physicians were not going to have time to take an entire course on polygenic risk scores. Instead, we wanted to design a lab report and informational resources that succinctly told the doctor and patient what they need to know to make a decision about using a polygenic risk score result in their healthcare,” epidemiologist Jason Vassy, MD, told The Harvard Gazette. Vassy is Associate Professor, Harvard Medical School at VA Boston Healthcare System and one of the authors of the research.
“This is another great example of precision medicine,” Jason Vassy, MD (above), Adjunct Assistant Professor, General Internal Medicine at Boston University School of Medicine, told WebMD. “There’s always been a tantalizing idea that someone’s genetic makeup might help tailor preventative medicine and treatment.” Personalized clinical laboratory testing is increasingly becoming based on an individual’s genetics. (Photo copyright: Harvard Medical School.)
Increasing Diversity of Patients in Genomic Research
The team did encounter some challenges during their analysis. Because most existing genomic research was performed on persons of European descent, the risk scores are less accurate among non-European populations. The researchers for this study addressed this limitation by applying additional statistical methods to qualify accurate PRS calculations across multiple racial groups.
“Researchers must continue working to increase the diversity of patients participating in genomics research,” said Matthew Lebo, PhD, Chief Laboratory Director, Laboratory Molecular Medicine, at Mass General Brigham and one of the authors of the study. “In the meantime, we were heartened to see that we could generate and implement valid genetic scores for patients of diverse backgrounds,” he told The Harvard Gazette.
The team hopes the scores may be utilized in the future to help doctors and patients make better decisions regarding preventative care and screenings.
“It’s easy to say that everyone needs a colonoscopy at age 45,” Vassy told WebMD. “But what if you’re such a low risk that you could put it off for longer? We may get to the point where we understand risk so much that someone may not need one at all.”
Future of PRS in Clinical Decision Making
The scientists plan to enroll more than 1,000 patients in a new program and track them for two years to assess how medical professionals use PRS in clinical care. It is feasible that patients who are at high risk for certain diseases may opt for more frequent screenings or take preventative medicines to mitigate their risk.
“Getting to that point will take time,” Vassy added. “But I can see this type of information playing a role in shared decision making between doctor and patient in the near future.”
The team also established resources and educational materials to assist both doctors and patients in using the scores.
“It’s still very early days for precision prevention,” Vassy noted, “but we have shown it is feasible to overcome some of the first barriers to bringing polygenic risk scores into the clinic.”
More research and studies are needed to prove the effectiveness of using PRS tests in clinical care and determine its role in customized treatment plans based on personal genetics. Nevertheless, pathologists and medical scientists will want to follow the GenoVA study.
“It is probably most helpful to think of polygenic risk scores as a risk factor for disease, not a diagnostic test or an indication that an individual will certainly develop the disease,” Vassy said. “Most diseases have complex, multifactorial etiologies, and a high polygenic risk score is just one piece of the puzzle.”
Pathologists and clinical laboratory managers may want to stay informed as researchers in the GenoVA study tease new useful diagnostic insights from their ongoing study of the whole human genome. Meanwhile, the GenoVA team is moving forward with the 1,000-patient study with the expectation that this new knowledge may enable earlier and more accurate diagnoses of the health conditions that were the focus of the GenoVA study.
