Medication use leading to emergency department visits for adverse drug events in older adults.

BACKGROUND The Beers criteria identify inappropriate use of medications in older adults. The number of and risk for adverse events from these medications are unknown. OBJECTIVE To estimate the number of and risk for emergency department visits for adverse events involving Beers criteria medications compared with other medications. DESIGN Nationally representative, public health surveillance of adverse drug events and a cross-sectional survey of outpatient medical visits. SETTING National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance System, 2004-2005; National Ambulatory Medical Care Survey, 2004; and National Hospital Ambulatory Medical Care Survey, 2004. PARTICIPANTS Persons 65 years of age or older seeking emergency department and outpatient care. MEASUREMENTS Estimated number of and risks for emergency department visits for adverse drug events involving Beers criteria medications and other medications. RESULTS Among U.S. patients 65 years of age or older, an estimated 177,504 emergency department visits (95% CI, 100,155 to 254,854 visits) for adverse drug events occurred both years. An estimated 3.6% (CI, 2.8% to 4.5%) of these visits were for adverse events medications considered to be always potentially inappropriate, according to the Beers criteria, and 33.3% (CI, 27.8% to 38.7%) of visits were for adverse events from 3 other medications (warfarin [17.3%], insulin [13.0%], and digoxin [3.2%]). Accounting for outpatient prescription frequency, the risk for emergency department visits for adverse events due to these 3 medications was 35 times (CI, 9.6 to 61) greater than that for medications considered to be always potentially inappropriate. LIMITATION Adverse events were identified only in emergency departments. CONCLUSION Compared with other medications, Beers criteria medications caused low numbers of and few risks for emergency department visits for adverse events. Performance measures and interventions targeting warfarin, insulin, and digoxin use could prevent more emergency department visits for adverse events.