Using Genomic Information to Improve Public Health
What exactly is precision medicine?
When the human genome was sequenced more than a decade ago, it began a new era of medicine that is now known as precision medicine. Initially, it was called personalized medicine; however, the word “personalized” was replaced with “precision” because it caused confusion and was misinterpreted. The goal of precision medicine is not to develop preventions and treatments that are unique for each individual. The National Research Council defines precision medicine as a medical model that focuses on “identifying which approaches will be effective for which patients based on genetic, environmental, and lifestyle factors.”
The role of electronic medical records
While the concept behind precision medicine sounds promising at the individual level, its application paradoxically requires population-level information. It is statistically and practically impossible to infer causality by working with single individuals each at a time. To learn what works and what does not for each individual, population-level data are necessary. For example, electronic medical records (EMRs) can be used to compare data on an individual with available information about other individuals to identify relevant risk factors, similar medical histories, and other vital information that can help patients and health care providers make informed decisions.
By acknowledging variations among humans, precision medicine incorporates more than just the easily collected variables such as age, gender, and co-morbidities. It takes into account more precise measurements about individuals such as genetic mutations, diet, physical activity, and occupancy. Thanks to advanced technologies, it has become increasingly cheap and easy to collect precise individual measurements. Nevertheless, such measurements are not being linked to EMRs. This is a lost opportunity to identify population subgroups that are likely to respond differently to medical interventions. With accurate genomic screening becoming more common, it is important for individuals and health care providers to integrate such information into their EMRs.
Precision medicine and health services utilization
The application of precision medicine has three major effects on health services utilization. First, it gives individuals and health care providers more predictive power to assess the marginal benefit of a certain intervention, whether it is a treatment or preventive intervention, and to better account/prepare for potential side effects. A great example is the recently FDA-approved drug Zykadia for lung cancer.
Second, it could lead to a greater use of effective preventive interventions, which could result in early detection of disease, reduced health-related costs, and improved health outcomes. This is the most promising aspect of precision medicine from a public health perspective. The intersection between precision medicine and public health has led to the creation of new field called “precision prevention.” This new field emphasizes the importance of disease prevention and the need to shift resources and priorities from clinical to public health practice. Innovative approaches of precision prevention use genomic information in health promotion and behavioral change science.
Third, it could reduce health services utilization by avoiding unnecessary medical interventions, which could also reduce health-related costs and exposure to medication-related toxicity. The 21-gene recurrence score assay Oncotype Dx is a promising example. This commercially available diagnostic test was developed in 2004 to predict the risk of cancer recurrence in women with newly diagnosed early-stage breast cancer. The test categorized breast cancer patients based on their recurrence scores into three categories: low, intermediate, and high risk. Patients with a low score receive no benefit from adjuvant chemotherapy while being exposed to the toxicity risk. Thus, it helps patients and health care providers make a well-informed decision about chemotherapy and whether it is necessary. Oncotype DX has been shown to improve population-based outcomes by reducing the number of patients experiencing adverse effects of chemotherapy.
Precision medicine is barely a decade old and we have yet to harness its potential. It is critical that public health and health services researchers include the relevant components of precision medicine into their work so that this perspective is represented, especially in policymaking and initiatives such as President Obama’s Precision Medicine Initiative.