Polypharmacy – or the use of multiple medications – is rising among older adults in the United States. In one study, 40 percent of people aged 65 and over reported the use of five or more prescription medications in the past month. Given that polypharmacy in older adults is associated with an increased risk of dangerous drug interactions and adverse drug events, a team of researchers from the University of North Carolina at Chapel Hill investigated potential problems linked specifically with medication use in older cancer patients.
[Photo: Drs. Jennifer Lund (left) and Til Stürmer]
The full article on their findings, “Potential Medication-Related Problems in Older Breast, Colon, and Lung Cancer Patients in the United States,” was published online Oct. 4 in the journal Cancer Epidemiology, Biomarkers & Prevention.
The study’s lead author was Dr. Jennifer L. Lund, assistant professor of epidemiology in the University of North Carolina Gillings School of Global Public Health. She was joined by five co-authors from UNC, including Dr. Til Stürmer, professor of epidemiology, and Ms. Virginia Pate, applications analyst, both in the Gillings School, as well as Dr. Hanna K. Sanoff, Dr. Hyman Muss and Ms. Sharon Peacock-Hinton, all with the UNC Lineberger Comprehensive Cancer Center, where Drs. Lund and Stürmer are members. (Dr. Stürmer also is director of the Center for Pharmacoepidemiology, where Dr. Lund is a member.)
“Older adults diagnosed with cancer are particularly vulnerable to the effects of polypharmacy, as a new diagnosis of cancer often requires cancer-directed treatments like surgery and chemotherapy, as well as a variety of medications aimed at managing both cancer symptoms and treatment side effects like nausea and diarrhea,” Dr. Lund explained. “Relatively little is known, however, about the potential for medication-related problems in older adults newly diagnosed with cancer in the United States.”
As the proportion of adults diagnosed with cancer at age 65 and over is expected to climb to 70 percent by 2030, medication management among this population is an important emerging public health concern.
To learn more, the researchers used Medicare data to estimate the monthly prevalence of potentially inappropriate medication use and potential drug-chemotherapy interactions in 33,838 patients over 65 years old and diagnosed with either stage I-III breast, stage II-III colon or stage I-II lung cancer.
They observed that, between 2004 and 2011, more than one in every three newly diagnosed adults was exposed to a potential medication-related problem. The prevalence of these problems in the year directly following cancer diagnosis was particularly high in patients whose cancers were being treated with chemotherapy; common drug interactions involved hydrochlorothiazide, warfarin and proton-pump inhibitors.
Before this research, only a handful of small studies had investigated the frequency of potential drug interactions involving chemotherapy in cancer patients, and none had evaluated the prevalence of potential medication-related problems over time following a cancer diagnosis. The new findings clarify the potential burden for specific medication-related problems in cancer patients receiving chemotherapy.
Still, Dr. Lund and her colleagues urge caution when interpreting their findings. They advocate for careful weighing of the risks and benefits of specific medications in the context of a new cancer diagnosis, especially because the expected benefits of cancer-directed treatment make these decisions particularly complex.
Their hope is that additional published information about the clinical outcomes of potential drug-chemotherapy interactions may help to guide the level of concern in patient consultations with pharmacy specialists.
“Older adults diagnosed with cancer have unique medication management needs,” Dr. Lund explained. “Therefore, we recommend that pharmacy specialists be routinely integrated into the multidisciplinary teams caring for these patients.”