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Sequencing the human genome created the tantalising promise of more personalised medicine. Futurists envisage a time when each individual undergoes genome sequencing at birth, stores the data on a chip or in an electronic health record (EHR), and allows healthcare providers to query it throughout one's life. Genomic medicine, the use of one's genotype in medical decision-making, may improve health outcomes, but the clinical translation of this vast body of scientific information is in its infancy. Nonetheless, some patients are eager to use genomic information to shape their healthcare now. Primary care providers (PCPs), however, may not share their patients' enthusiasm for this new technology. Prioritising actions supported by an evidence base of efficacy, safety and cost-effectiveness, PCPs identify many barriers to the use of genomic medicine.1
The genomic medicine evidence base
The potential benefits of genomic medicine include improved disease risk assessment, selection of therapy and drug dosing. Its potential adverse effects include patient anxiety and the unnecessary and expensive tests and procedures that might follow from a genomic result.2 Despite rapid advances in understanding the genetic architectures of many diseases, translational research into the outcomes of their clinical applications has lagged. The full risk-benefit ratio is thus unknown for almost all genomic tests, particularly for long-term outcomes. Primary care has a culture of evidence-based medicine that seeks to maximise health benefits and minimise unnecessary harms to patients. Consequently, PCPs may be reluctant to integrate genomics into clinical practice. Certain genomic tests have been better studied than others. Variants in the BRCA1/2 genes have proven implications for the risk assessment and management of hereditary breast and ovarian cancer. In the USA, the Food and Drug Administration has included pharmacogenomic considerations for efficacy and safety on the labels of more than 100 medications including clopidogrel, warfarin and citalopram.3 However, developing an evidence base for most genomic tests comparable to what is known about BRCA testing, for example, will require decades of research. Pending such research, however, PCPs can take comfort in a situation familiar to primary care: having to make clinical decisions despite an absence of sufficient evidence. PCPs are experts at combining the available evidence with professional judgement and open communication to make medical decisions with the individual patients in front of them. At the same time, their call for clinical and patient-centred outcomes will be a critical contribution to shaping the genomics research agenda moving forward.
The last decade has seen unprecedented genomic discovery and also major clinical advances in the management of common diseases including cardiovascular disease and cancer. In an environment with limited time for reading new medical literature, PCPs may not prioritise learning about genomic medicine. Moreover, many PCPs profess low confidence in their ability to use genetic information to make clinical decisions.4 This challenge is not new to primary care; medical discovery always outpaces an individual's ability to master it. However, PCPs have several resources to help them adapt to new medical knowledge, including genomic medicine. The first is the emphasis on generalism that originally attracts many to primary care. The value of having a broad knowledge base spurs PCPs to read the medical literature widely while prioritising what is important to their patients' health. They often rely on clinical guidelines and resources from expert panels (table 1). They also cultivate networks of trusted colleagues through both informal ‘curbside’ and formal consultations. With the rise of genomic medicine, these networks will increasingly include genetics professionals, although their supply may be insufficient to meet growing demand. Knowledge learned through such interactions around one patient may apply to future similar patients. Generalists are also innovators in designing systems to help manage complex medical information. Clinical decision support is increasingly being introduced into EHRs across North America to alert prescribers about adverse drug interactions or to remind physicians about overdue health maintenance. Efforts are already underway to incorporate genomic data into the EHR and create systems to help manage large quantities of rapidly changing genetic information.5 Moving forward, primary care residencies may also increasingly include genomics education.6 ,7
Evidence gaps and lack of physician knowledge will not deter some patients from seeking genomic testing. Even without demonstrated clinical utility (defined here narrowly as a favourable balance of benefits and risks for health and disease outcomes8), patients in certain parts of the world may still request whole genome sequencing or seek direct-to-consumer genetic testing out of a belief that it will equip them to improve their health. A misalignment of patient and physician values may result. But while PCPs may believe that the clinical utility of such genetic testing does not merit its incorporation into their practices, patients' perceptions of its personal utility might. This concept incorporates a respect for each patient's health attitudes and preferences and is a central tenet of primary care. If providers do not meaningfully engage with patients in the health information they value, they may risk undermining the therapeutic relationship. Effective PCPs already use these episodes of patient engagement with their health as teachable moments to discuss medical evidence and explore the underlying health beliefs and values and personal preferences. These conversations can use existing models of shared decision-making that present options, discuss their risks and benefits and elicit patient preferences.9 In the case of genomic medicine, PCPs should educate patients about its limits and the potential harms of uncertain and unwanted information while listening to patients' beliefs and preferences for engaging with their genetic make-up.
PCPs have a real opportunity to lead the discussion on the role of genomic medicine in patient care. The concepts of shared decision-making and patient-centred care comprise the bedrock of primary care. These ideals have grown out of both a respect for patient autonomy in healthcare and also the pragmatic recognition that health can only be achieved if the patient is a partner in the medical process. In listening to their patients' values regarding genomic medicine, PCPs have the opportunity to harness those values for health.
Contributors All three authors made substantial contributions to the conception, writing and revision of the manuscript.
Funding This work was supported by National Institutes of Health grants U01-HG006500, R01-HG005092, K24-AG027841 and L30-DK089597.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.
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