Researchers at Columbia University College of Physicians and Surgeons have just published a study that provides a foundation for pharmacogenetic testing for gene mutations that affect drug metabolism in older adults. Many of these mutations explain higher hospitalization rates for some older adults taking multiple medications. The results of this new study were published online in Pharmacogenetics and Personalized Medicine through an article entitled “Pharmacogenetic polymorphism as an independent risk factor for frequent hospitalizations in older adults with polypharmacy: a pilot study.”
The use of multiple medications, often referred to as polypharmacy, is on the rise among U.S. seniors. Nearly 40% of Americans 65 or older take at least five or more medications. Yet, previous studies have shown that older adults with polypharmacy are more prone to adverse events and hospitalizations than those taking fewer medications. Though few studies have investigated individual, genetic risk factors for adverse drug events in this population.
In this pilot study, the investigators hypothesized that older adults with polypharmacy and increased hospitalization rates would have more genes associated with altered drug metabolism or lack of sensitivity to certain drugs than those with fewer hospitalizations.
The Columbia team completed pharmacogenetic testing to identify five genes—CYP2C19, CYP2C9, VKORC1, CYP2D6, and CYP3A4/5—in older adults with polypharmacy. The study included six seniors who had been admitted to the hospital at least three times over the past two years and six age-matched controls who had fewer hospitalizations. Both groups had an average age of 77 years and were taking an average of 14 medications.
"Although this was a very small pilot study, the findings suggest that routine testing for these gene variants could improve health outcomes for older adults taking multiple medications," explained lead study author Joseph Finkelstein, M.D., Ph.D., director of the Center for Bioinformatics and Data Analytics in Oral Health at the Columbia University College of Dental Medicine and associate professor of health informatics in dentistry at Columbia University Medical Center. "In dentistry, for example, pharmacogenetic testing could be part of a personalized approach in which clinicians select pain medications that are most effective and least risky for each patient."
Specifically, in the higher hospitalization group, each of the participants had at least one of the mutations, and half had more than one. None of the controls had any of the mutations.
Due to the small size of the pilot study, the Columbia investigators are planning a larger clinical trial to investigate whether the identification of drug-metabolism-altering mutations in adults with polypharmacy may improve outcomes.