Direct-to-Consumer Pharmacogenomic Testing
Direct-to-Consumer Pharmacogenomic Testing
Receipt of a commercially available DTC PGx risk test was associated with increases in physician utilisation among a selected sample of individuals. Specifically, PGx test recipients were 1.5 times more likely to share their genomic results with their physician than non-recipients. PGx recipients also showed a statistically significant increase in the number of physician visits from baseline to follow-up relative to non-recipients, though importantly, the average increase, as well as average difference from non-recipients, was less than one visit. Our data and sample size do not permit us to assess the cost-effectiveness of DTC PGx testing for the panel of drug-gene pairs for which our participants received results, or whether testing resulted in improved precision in prescriptions leading to avoidance of major side effects or assurance of efficacy or optimal dosing. It is worth noting, however, that while the Agency for Healthcare Research and Quality reported that in 2006, an office physician visit cost $180 on average, costs associated with adverse drug events are known to be at least an order of magnitude higher, reflecting the need for hospitalisations, and some are associated with fatal outcomes. Our findings further highlight the need for more research, including cost-effectiveness studies, on the impact of DTC genomic risk testing on patients, physicians and healthcare systems.
The largest consumer genomics company, 23andMe, has now sold their genomic testing panel to over 200 000 individuals. The panel costs $99 and includes PGx testing for over 20 medications, including the majority of the drug-DNA variant interactions in the present study. Accordingly, cost-effectiveness can be assessed in the context of the diminishing cost for a fairly extensive PGx panel.
An emerging literature documenting the lack of physician education, training and knowledge in genomics is relevant to our findings. For instance, a recent survey found that only 10% of physicians felt he or she had the necessary training and knowledge in genomics to provide adequate care in this area to their patients, and other studies have produced similar findings. Fortunately there are a handful of recently initiated efforts to bridge this gap, but significant work remains. This is underscored by our findings that a large fraction of DTC genomic test consumers, and an even larger fraction of PGx test recipients specifically, do turn to their physicians spontaneously with their results, presumably for additional advice and counsel regarding how their genomic findings may impact their health generally and prescription drug use specifically. Notably, PGx recipients in our sample were also more likely to discuss their results with a genetic counsellor, a service that was offered to all participants free of charge. While this finding raises questions regarding the possible importance of making genetic counselling services available to individuals undergoing PGx risk testing, it also exposes potential problems stemming from the very low numbers of trained genetic counsellors in the USA.
Importantly, our sample consisted of a self-selected group of individuals, likely representative of the current population of consumers of DTC genomic testing, who chose to undergo and pay out of pocket for testing. In comparison, another study of a young (age 25–40 years), healthy, insured population found lower levels of baseline utilisation, as well as no difference in the use of health services before and after free multiplex genetic risk testing for eight common diseases (the study did not offer or provide PGx testing to participants). In addition to the fact that PGx results were not provided, other factors that may account for differences in findings between these two studies are the inclusion of individuals in our study who were much older (up to age 80+ years) and therefore perhaps more likely to have higher rates of baseline utilisation, the possibility that cost-sharing for the test in our study motivated increased healthcare seeking behaviours, as well as the relatedly high income and education levels of our sample. Taken together, observations from each study raise several hypotheses, including that responses to genetic testing may be test specific (ie, testing for PGx vs complex disease risk), cost structure specific (ie, free vs co-pay), and somewhat population and demographic specific. Further work is needed to better understand the impacts of DTC PGx risk testing on representative samples of individuals in USA and other countries in which consumers are purchasing such tests.
PGx testing was not associated with changes in psychological health or increases in test-related distress. In addition, while the large majority of participants in both groups reported that the DTC genomic test was useful, understandable, and that they did not have privacy concerns, PGx test recipients were somewhat more likely to perceive their test results as useful, understandable and to indicate privacy concerns (14% of PGx recipients vs 11% of non-recipients). This latter finding regarding privacy concerns is notable, and it is unclear what may be driving this observation. One possibility is that PGx information may be more likely to be used by physicians and or added to an individual's medical record, which may be concerning for some individuals who choose to undergo testing. Consistent with this, we and others have found evidence that some groups of DTC genomic test consumers may be hesitant to share or discuss their genetic results with a healthcare provider precisely because of privacy concerns. Further research will be needed to better understand this result and possible explanations. The finding that PGx test recipients were also more likely to rate the test as more understandable is somewhat counterintuitive. It is possible that PGx recipients were answering this question with the PGx results in mind while those who were still awaiting their results had the more uncertain complex disease risk results in mind.
It is also notable that a very large proportion of our sample reported sharing their results with family members (over 80% in both groups), and that those who received PGx testing were statistically more likely to recommend testing to family and non-family members. This suggests that within the context of the DTC model, consumers also seek health-related counsel and support from other sources, including family. Testing may serve to engender health-related discussions within families and promote more accurate knowledge of family disease and prescription drug use histories, something that has been promoted by prominent public health groups, including the US Centers for Disease Control and Prevention.
Our study has some limitations. First, we studied a sample of convenience that consisted of individuals who elected to undergo DTC genomic testing for common disease risk. As such, though our sample has been shown to be representative of the current population of consumers of DTC genomic tests, it is not representative of the general population (ie, given the high education and income of the sample, and the fact that over 99% of individuals had health insurance), and therefore it is unknown how these findings may or may not generalise to a broader population. Second, though our sample size is relatively large as compared with typical behavioural studies of response to genetic and genomic information, it was not adequate to address some questions of interest. For instance, given the low frequency of some of the genetic variants included on the PGx test panel, coupled with the relatively low frequency of use of any of the medications on the panel among individuals in our sample, it does not allow us to document whether or to what degree DTC PGx testing resulted in improved precision in prescriptions leading to better drug-related outcomes. Third, although we did assess differences between PGx recipients and non-recipients in the number of non-physician visits at follow-up, we did not specifically evaluate the extent to which participants may have shown differences specifically in their utilisation of pharmacists, which would be an important question to pose in future studies. Fourth, we did not use a design in which participants were randomised to have either received PGx or be on a wait-list control. Finally, the data collected also do not distinguish how many physician visits occurred after receipt of PGx results and, similarly, data are not available on whether results disclosed to physicians were PGx results or other DTC results, or whether additional tests ordered or counsellor visits were PGx-related. Further, it is possible that the increase in the number of physician visits could be due to the effect of getting more information, rather than PGx-information-specific effects.
Our study also relied on brief, web-based, self-report assessment of health behaviours. Although such assessments are not ideal as they can be less reliable and more prone to participant recall biases than inperson assessment, studies have suggested strong correlations between self-reported and medical records-based healthcare utilisation rates. Our findings are also based on a single follow-up assessment and do not speak to the effects of PGx testing over the course of multiple years, allowing for a timeframe in which some participants may develop health issues that may require the use of one or more medications included in the panel.
In conclusion, DTC PGx risk profiling among a selected sample of persons was associated with statistically significant increases in physician utilisation. PGx testing did not result in any short-term changes in psychological health. Further evaluation of the utility and cost considerations for DTC PGx testing appear to be warranted.
Discussion
Receipt of a commercially available DTC PGx risk test was associated with increases in physician utilisation among a selected sample of individuals. Specifically, PGx test recipients were 1.5 times more likely to share their genomic results with their physician than non-recipients. PGx recipients also showed a statistically significant increase in the number of physician visits from baseline to follow-up relative to non-recipients, though importantly, the average increase, as well as average difference from non-recipients, was less than one visit. Our data and sample size do not permit us to assess the cost-effectiveness of DTC PGx testing for the panel of drug-gene pairs for which our participants received results, or whether testing resulted in improved precision in prescriptions leading to avoidance of major side effects or assurance of efficacy or optimal dosing. It is worth noting, however, that while the Agency for Healthcare Research and Quality reported that in 2006, an office physician visit cost $180 on average, costs associated with adverse drug events are known to be at least an order of magnitude higher, reflecting the need for hospitalisations, and some are associated with fatal outcomes. Our findings further highlight the need for more research, including cost-effectiveness studies, on the impact of DTC genomic risk testing on patients, physicians and healthcare systems.
The largest consumer genomics company, 23andMe, has now sold their genomic testing panel to over 200 000 individuals. The panel costs $99 and includes PGx testing for over 20 medications, including the majority of the drug-DNA variant interactions in the present study. Accordingly, cost-effectiveness can be assessed in the context of the diminishing cost for a fairly extensive PGx panel.
An emerging literature documenting the lack of physician education, training and knowledge in genomics is relevant to our findings. For instance, a recent survey found that only 10% of physicians felt he or she had the necessary training and knowledge in genomics to provide adequate care in this area to their patients, and other studies have produced similar findings. Fortunately there are a handful of recently initiated efforts to bridge this gap, but significant work remains. This is underscored by our findings that a large fraction of DTC genomic test consumers, and an even larger fraction of PGx test recipients specifically, do turn to their physicians spontaneously with their results, presumably for additional advice and counsel regarding how their genomic findings may impact their health generally and prescription drug use specifically. Notably, PGx recipients in our sample were also more likely to discuss their results with a genetic counsellor, a service that was offered to all participants free of charge. While this finding raises questions regarding the possible importance of making genetic counselling services available to individuals undergoing PGx risk testing, it also exposes potential problems stemming from the very low numbers of trained genetic counsellors in the USA.
Importantly, our sample consisted of a self-selected group of individuals, likely representative of the current population of consumers of DTC genomic testing, who chose to undergo and pay out of pocket for testing. In comparison, another study of a young (age 25–40 years), healthy, insured population found lower levels of baseline utilisation, as well as no difference in the use of health services before and after free multiplex genetic risk testing for eight common diseases (the study did not offer or provide PGx testing to participants). In addition to the fact that PGx results were not provided, other factors that may account for differences in findings between these two studies are the inclusion of individuals in our study who were much older (up to age 80+ years) and therefore perhaps more likely to have higher rates of baseline utilisation, the possibility that cost-sharing for the test in our study motivated increased healthcare seeking behaviours, as well as the relatedly high income and education levels of our sample. Taken together, observations from each study raise several hypotheses, including that responses to genetic testing may be test specific (ie, testing for PGx vs complex disease risk), cost structure specific (ie, free vs co-pay), and somewhat population and demographic specific. Further work is needed to better understand the impacts of DTC PGx risk testing on representative samples of individuals in USA and other countries in which consumers are purchasing such tests.
PGx testing was not associated with changes in psychological health or increases in test-related distress. In addition, while the large majority of participants in both groups reported that the DTC genomic test was useful, understandable, and that they did not have privacy concerns, PGx test recipients were somewhat more likely to perceive their test results as useful, understandable and to indicate privacy concerns (14% of PGx recipients vs 11% of non-recipients). This latter finding regarding privacy concerns is notable, and it is unclear what may be driving this observation. One possibility is that PGx information may be more likely to be used by physicians and or added to an individual's medical record, which may be concerning for some individuals who choose to undergo testing. Consistent with this, we and others have found evidence that some groups of DTC genomic test consumers may be hesitant to share or discuss their genetic results with a healthcare provider precisely because of privacy concerns. Further research will be needed to better understand this result and possible explanations. The finding that PGx test recipients were also more likely to rate the test as more understandable is somewhat counterintuitive. It is possible that PGx recipients were answering this question with the PGx results in mind while those who were still awaiting their results had the more uncertain complex disease risk results in mind.
It is also notable that a very large proportion of our sample reported sharing their results with family members (over 80% in both groups), and that those who received PGx testing were statistically more likely to recommend testing to family and non-family members. This suggests that within the context of the DTC model, consumers also seek health-related counsel and support from other sources, including family. Testing may serve to engender health-related discussions within families and promote more accurate knowledge of family disease and prescription drug use histories, something that has been promoted by prominent public health groups, including the US Centers for Disease Control and Prevention.
Our study has some limitations. First, we studied a sample of convenience that consisted of individuals who elected to undergo DTC genomic testing for common disease risk. As such, though our sample has been shown to be representative of the current population of consumers of DTC genomic tests, it is not representative of the general population (ie, given the high education and income of the sample, and the fact that over 99% of individuals had health insurance), and therefore it is unknown how these findings may or may not generalise to a broader population. Second, though our sample size is relatively large as compared with typical behavioural studies of response to genetic and genomic information, it was not adequate to address some questions of interest. For instance, given the low frequency of some of the genetic variants included on the PGx test panel, coupled with the relatively low frequency of use of any of the medications on the panel among individuals in our sample, it does not allow us to document whether or to what degree DTC PGx testing resulted in improved precision in prescriptions leading to better drug-related outcomes. Third, although we did assess differences between PGx recipients and non-recipients in the number of non-physician visits at follow-up, we did not specifically evaluate the extent to which participants may have shown differences specifically in their utilisation of pharmacists, which would be an important question to pose in future studies. Fourth, we did not use a design in which participants were randomised to have either received PGx or be on a wait-list control. Finally, the data collected also do not distinguish how many physician visits occurred after receipt of PGx results and, similarly, data are not available on whether results disclosed to physicians were PGx results or other DTC results, or whether additional tests ordered or counsellor visits were PGx-related. Further, it is possible that the increase in the number of physician visits could be due to the effect of getting more information, rather than PGx-information-specific effects.
Our study also relied on brief, web-based, self-report assessment of health behaviours. Although such assessments are not ideal as they can be less reliable and more prone to participant recall biases than inperson assessment, studies have suggested strong correlations between self-reported and medical records-based healthcare utilisation rates. Our findings are also based on a single follow-up assessment and do not speak to the effects of PGx testing over the course of multiple years, allowing for a timeframe in which some participants may develop health issues that may require the use of one or more medications included in the panel.
In conclusion, DTC PGx risk profiling among a selected sample of persons was associated with statistically significant increases in physician utilisation. PGx testing did not result in any short-term changes in psychological health. Further evaluation of the utility and cost considerations for DTC PGx testing appear to be warranted.
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