Nearly 100,000 Americans aged 65 years and older are hospitalized each year after adverse drug events, and most of these emergencies result from a few commonly used medications, according to a study from the Centers for Disease Control and Prevention.
Of an estimated 99,628 hospitalizations – about half coming among people aged 80 years and older – 66% were the result of unintentional overdoses, Dr. Daniel S. Budnitz, director of the CDC’s Medication Safety Program, and his colleagues reported in the Nov. 24 issue of the New England Journal of Medicine.
The medications most often implicated were warfarin, insulins, oral antiplatelet agents, and oral hypoglycemic agents, which either alone or in combination accounted for 33%, 14%, 13%, and 11% of the hospitalizations, respectively, the investigators reported (N. Engl. J. Med. 2011;365:2002-12).
Emergency department visits resulting in hospitalization were more likely than those not resulting in hospitalization to involve unintentional overdoses (66% vs. 46%) and to involve at least five medications (55% vs. 40%).
The researchers noted that medications typically deemed high risk or inappropriate for elderly patients resulted in relatively few emergency hospitalizations, accounting for only about 1% and 7% of the 65-and-over emergency admissions, respectively.
The findings have important implications for reducing harm and health care costs among older adults, said Dr. Budnitz and his colleagues. Such detailed and drug-specific data can help focus current patient-safety efforts, such as the Partnership for Patients, they said. That $1 billion federal initiative has the goal of decreasing preventable hospitalizations 20% by the end of 2013.
The investigators used adverse-event data for 2007 through 2009 from the National Electronic Injury Surveillance System – Cooperative Adverse Drug Event Surveillance Project. They based their national estimates on an analysis of 5,077 emergency hospitalizations in older adults at 58 nonpediatric hospitals that participate in the surveillance system.
The numbers probably represent underestimates of emergency hospitalizations, the investigators said. They explained that some patient groups – such as those admitted for diagnostic evaluation or transferred from other hospitals – were not represented in the analysis.
"Our findings suggest that efforts to improve medication safety for older adults should focus on areas in which improvements are most likely to have sizable, clinically significant, and measurable effects, such as improving the management of antithrombotic and antidiabetic drugs," the investigators concluded.
In a press statement, Dr. Budnitz acknowledged that blood thinners and diabetes medications are critical medicines for many older adults. "Doctors and patients should continue to use them but remember to work together to safely manage them," he said.
Neither Dr. Budnitz nor any of the other investigators disclosed any conflict of interest.