Frailty not a factor in adverse drug reactions among seniors, study finds

Contrary to popular belief among physicians, frailty in elderly patients is not associated with an increased risk of adverse reactions to medications, according to a study led by Michael Steinman, MD, a geriatrician at the San Francisco VA Medical Center.

The study of 377 patients age 65 or older appears in the online Early View section of the Journal of the American Geriatrics Society.

"There is a common, and reasonable, perception among clinicians that older people who are unable to carry out activities of daily living such as bathing, dressing, and walking without assistance are more vulnerable to adverse reactions from new medications," said Steinman, who is also an assistant professor of medicine at the University of California, San Francisco. "However, we found no association between degree of frailty and a patient's risk of adverse drug reactions."

Instead, Steinman and his fellow researchers found evidence to suggest that the greatest risk factor for an adverse drug reaction was the number of new medications that had been added recently to a patient's medication regimen.

This makes sense, observed Steinman. "If you've been on a drug for a while, the chance of your suddenly developing an adverse reaction to it is relatively low," he said, "whereas when you start a new drug, that's the time when most adverse reactions will occur."

Steinman cautioned that the study is not definitive. "Nonetheless," he said, "this indicates to physicians that they should not necessarily let their concerns about adverse reactions overrule other considerations" when deciding whether to prescribe a potentially beneficial drug to a frail elderly patient. "We want to exercise due caution," he noted, "but we don't need to be as fearful as we think we do when prescribing for our older patients."

Co-authors of the study are Brian C. Lund, PharmD, of Iowa City VA Medical Center and the University of Iowa; Yinghui Miao, MPH, of SFVAMC; W. John Boscardin, PhD, of SFVAMC and UCSF; and Peter J. Kaboli, MD, of ICVAMC and UI.

The study was supported by funds from the National Institute on Aging, the American Federation for Aging Research, the Department of Veterans Affairs, and the Center for Research in the Implementation of Innovative Strategies in Practice at ICVAMC. Some of the funds were administered by the Northern California Institute for Research and Education.

NCIRE - The Veterans Health Research Institute - is the largest research institute associated with a VA medical center. Its mission is to improve the health and well-being of veterans and the general public by supporting a world-class biomedical research program conducted by the UCSF faculty at SFVAMC.

SFVAMC has the largest medical research program in the national VA system, with more than 200 research scientists, all of whom are faculty members at UCSF.

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.

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