Published: Aug. 9, 2004
Updated: Nov. 3, 2004
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By Duke Medicine News and Communications
DURHAM, N.C. -- Many Americans over the age of 65 hold prescriptions for drugs considered potentially risky for elderly patients, according to a new study by Duke University Medical Center researchers. The finding emphasizes a need for greater awareness among physicians about the risks presented by commonly prescribed medications as people age and for additional measures to monitor prescription drug use, the team said.
The Duke researchers found that over the course of a year one in five elderly Americans whose benefits were processed by one of the largest pharmaceutical benefits managers in the U.S. filled a prescription for at least one drug classified as a "drug of concern," according to established criteria known as the Beers list. Of those claims, half were for drugs -- including the anti-depressant amitriptyline (Elavil®, Endep®, Vanatrip®) and anti-anxiety drug diazepam (Valium®) -- with potential for severe adverse effects in older people, the researchers reported in the Aug. 9, 2004, issue of Archives of Internal Medicine.
"Although criteria for drugs to avoid in the elderly have been around for a long time, the amount of potentially inappropriate prescribing for older patients remains really high," said Lesley Curtis, Ph.D., a member of the Duke Center for Clinical and Genetic Economics and lead author of the study. The center is part of the Duke Clinical Research Institute. The work was supported by a Centers for Education and Research on Therapeutics cooperative agreement between the Agency for Healthcare Research and Quality in Rockville, Md., and the University of Arizona Health Sciences Center in Tucson.
People over the age of 65 make up less than 15 percent of the U.S. population, yet they account for nearly one-third of drug consumption, noted Kevin Schulman, M.D., director of the Duke Center for Clinical and Genetic Economics and senior author of the study. Elderly individuals more often have multiple chronic conditions, increasing the likelihood that they take several drugs concurrently, he added. Furthermore, many drugs present increasing risk for people as they age due to changes in metabolism and excretion, whose effects are complicated by the number of prescription drugs taken.
The list of criteria for determining the appropriate use of medication in elderly living in nursing homes was developed in 1991 by a team led by Mark Beers at the University of California, Los Angeles, culled from the opinions of a panel of experts. In 1997, Beers updated the original list, initially intended primarily for institutional use, for use in any setting. The list named 28 medications or classes of medications considered inappropriate for use in elderly patients. The panel deemed 14 of those 28 medications to have potentially severe adverse outcomes when taken by older people.
In the current study, the Duke team analyzed the prescriptions filled for all patients over 65 who filed claims in 1999 through the outpatient prescription claims database of AdvancePCS (now part of Caremark Rx, Inc.). The study population included representatives of all 50 states, the District of Columbia, Puerto Rico and two U.S. territories.
Of the 765,423 people included in the study, more than 20 percent (162,370) filled a prescription for one or more drugs of concern during the year, they reported. While most patients who made such a claim filled a prescription for a single Beers list drug, nearly 16 percent (25,550) made claims for two risky drugs and 4 percent (6,402) filled prescriptions for three or more Beers list drugs within the same year.
In the study, 41 percent of elderly beneficiaries who filled a prescription for a drug on the Beers list did so for a psychotropic drug. Claims for the anti-depressants amitriptyline and doxepin (Adapin®, Sinequan®, Zonalon®) alone accounted for nearly one quarter of the total claims for drugs considered potentially risky for elderly patients, the team reported. Neuromuscular agents ranked second among the most commonly prescribed classes of Beers list drugs.
The results mirror those of an earlier study of prescriptions to the elderly in 1987, which found that 23.5 percent of elderly patients filled prescriptions for one or more of the Beers list drugs, Curtis added. "Despite earlier warnings, we're not getting any better in the use of these drugs," she said.
The findings suggest that some doctors may be uninformed about the increasing risks presented by common medications as people age, Curtis said. Others might be familiar with the list, but believe that the benefits outweigh the risks in some situations, she added.
The team notes that pharmaceutical claims databases could offer a useful tool to help reduce the problem by screening prescriptions and issuing patient-specific alerts when physicians prescribe inappropriate drugs or drug combinations, she said. Physicians' compliance with the guidelines might also be improved by bolstering the clinical evidence for the risks presented by particular drugs when taken by older patients, she added, noting that the elderly are rarely included in the clinical trials that generate information about drugs' side effects.
Archives of Internal Medicine published a more recent update of the Beers list including 48 medications or classes of medications to avoid in adults age 65 or older in their Dec. 8, 2003, issue.
Collaborators on the study include Truls Ostbye, M.D., and Veronica Sendersky, of Duke; Steve Hutchison, Ph.D., Peter Dans, M.D., and Alan Wright, M.D., of AdvancePCS; and Raymond Woosley, M.D., of University of Arizona Health Sciences Center.