A 21st Century Approach to Personalized Medicine: Using Genetic Code to Determine Dosage of Blood Thinner

By Jacqueline Katz

Warfarin, most commonly referred to as Coumadin, has been used for decades to prevent the formation of blood clots, often recommended to patients recovering from hip or knee replacement surgery. And for decades, doctors have prescribed this blood thinner based on clinical factors including age, height, weight, gender, and race. It is the prevalence of the drug that prompted researchers to take another look: “Over the last 10 years, warfarin has led to more medication-related emergency room visits among older adults than any other drug.”

Within the past couple weeks, the Journal of the American Medical Association came out with a new warfarin study. It detailed that working from a patient’s genetic profile along with other known clinical factors to determine the optimal dosage of blood thinner vastly reduced the risk of major bleeding and, on the other side, the formation of blood clots.

The study was conducted on 1,600 individuals age 65 and older undergoing hip or knee replacement surgery. Patients were separated randomly into two groups. One group received warfarin dosing based on purely clinical factors, and the second group's dose was based on these factors in addition to information extracted from each patient’s genetic code.

While fifteen percent of the patients whose dosages were calculated through the traditional metric experienced at least one adverse effect, a mere eleven percent of patients whose warfarin dosing was guided by genetic testing saw any unfavorable effects. A margin of four percent may seem meaningless to the untrained eye, but this difference is “statistically significant.” However, even more important, this study shows a practical use for genetic testing and sets a precedent for future experimental methods.


Hospital for Special Surgery. (2017, September 26). Genetic testing can help determine safest dose of blood thinner. ScienceDaily. Retrieved October 7, 2017 from www.sciencedaily.com/releases/2017/09/170926143556.htm