Common Drugs Key in Emergency Admissions for Seniors

By Michael Smith, North American Correspondent, MedPage Today
Published: November 23, 2011
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.

Action Points
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â–*In this study almost half of hospitalizations for drug adverse events occurred in adults 80 years of age or older.

â–*Four commonly used medications accounted for 67% of all emergency admissions for drug adverse events hospitalizations.

Better management of antithrombotic and anti-diabetic drugs could help avoid thousands of emergency admissions for adverse drug events in older adults every year, researchers reported.

Every year, nearly 100,000 adults 65 or over have an emergency hospital admission, mainly because of a few commonly used drugs or drug classes, according to Dan Budnitz, MD, of the CDC in Atlanta.

High-risk and inappropriate drugs, on the other hand, only accounted for a small fraction of the emergency admissions, Budnitz and colleagues reported in the November 24 issue of the New England Journal of Medicine.

The implication, Budnitz said in a statement, is that "focusing safety initiatives on a few medicines that commonly cause serious, measurable harms can improve care for many older Americans."

The main culprits -- accounting for more than two-thirds of all such admissions -- are warfarin, insulins, oral antiplatelet agents, and oral hypoglycemic agents, the researchers reported.

But drugs designated as high-risk for older people in the 2011 Healthcare Effectiveness Data and Information Set only accounted for 1.2% of emergency admissions. Drugs defined as "potentially inappropriate" for older adults in the Beers criteria led to 6.6% of admissions.

The findings are an analysis of data from a nationally representative sample of 58 hospitals that took part in the CDC's National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project between 2007 and 2009.

Budnitz and colleagues reported that the hospitals saw 5,077 emergency admissions over the study period, yielding a national estimate of 99,628 a year (95% CI 55,531 to 143,724).

Nearly half of those admissions (48.1%) were among adults 80 or older and 65.7% were due to unintentional overdoses, they found.

Four medications or medication classes were implicated, either alone or in combination, in 67% of all emergency admissions for drug adverse events, the researchers found. Specifically:
•Warfarin accounted for an estimated 33,171 admissions a year, or 33.3% of the total
•Insulins were blamed for 13,854 admission a year, or 13.9% of the total
•Oral antiplatelet agents accounted for 13,263 cases, or 13.3%
•And oral hypoglycemic agents led to 10,656 admissions, or 10.7%

Those remained the most common causes of admission regardless of age, Budnitz and colleagues reported.

Nearly all admissions involving warfarin, insulins, or oral hypoglycemic agents involved accidental overdoses at 95.1%, 99.4%, and 99.1%, respectively, the researchers found.

More than half of the admissions involving "inappropriate" Beers-criteria medications were caused by digoxin, the researchers found. When digoxin was excluded, Beers-criteria medications were implicated in only 3.2% of admissions.

The study implies, Budnitz and colleagues concluded, that improved management of antithrombotic and anti-diabetic drugs could have "sizable, clinically significant, and measurable effects" on public health.

They cautioned that the analysis probably underestimated the true number of emergency admissions, because the database would leave out some cases, including those in which the drug at issue was identified through patient interview after admission.

The study also did not have direct estimates of person-year exposure to medications, they noted.

The authors are all employees of the CDC. They did not report any external support for the study.

Primary source: New England Journal of Medicine
Source reference:
Budnitz DS, et al "Emergency hospitalizations for adverse drug events in older Americans" N Engl J Med 2011; 365: 2002-2012.

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