Clinical question: The purpose of this study was to describe emergency department (ED) visits for adverse drug events in year 2013-2014 compared to year 2005-2006 to learn changing patterns of ADEs and to help advance medication safety initiatives in outpatient settings.
Background: Adverse drug events (ADEs) are the most common cause of iatrogenic harm to patients and there have been significant national-level initiatives to prevent them as a part of patient safety. In the outpatient setting, where 90% of prescription drug expenditures occur, preventing ADEs remains a patient safety challenge because patients can have complex medication regimens, at times prescribed by multiple clinicians, with far less monitoring compared with hospitalized patients.
Setting and study design: Active, public health surveillance in 58 EDs in the United States that participate in the National Electronic Injury Surveillance System–Cooperative Adverse Drug Event Surveillance Project (NEISS-CADES). Trained data abstractors at each hospital reviewed each ED visit to identify any clinician-diagnosed ADEs that were the reason for the ED visit. Reports were coded by CDC and analyzed.
Synopsis: Based on 42,585 cases, 4.0 (95% CI, 3.1-5) ED visits for ADEs per 1,000 individuals occurred annually in the United States in 2013-2014 and 27.3% (22.2%-32.4%) of ED visits for ADEs resulted in hospitalization.
An estimated 34.5 % (95% CI, 30.3-38.8) of ED visits for ADEs occurred among adults aged 65 or older in 2013 compared with an estimated 25.6% (95% CI, 21-30) in 2005-2006. The population rate for adults older than 65 years was 9.7 visits per 1,000 individuals, compared with 3.1 visits per 1,000 individuals for those younger than 65 years. Older adults experienced higher hospitalization rates 43.6% (95% CI, 36.6-50.5). When adjusted for the U.S. population, the hospitalization rate for ADEs among older individuals was seven times higher compared with younger patients.
A single medication was implicated in most ED visits for ADEs (83.8%; 95% CI, 81.5-86.1). Supratherapeutic effects of ingestion of excess dose was the most common type of ADE (37.2%; 95% CI, 34.7-39.6). Medication errors were documented in 1 of 10 ED visits for ADEs (10.5%; 95% CI, 8.9-12.2).
The most commonly implicated drug classes were anticoagulants (17.6%), systemic antibiotics (16.1%), diabetes agents (13.3%), opioid analgesics (6.8%), antiplatelets (6.6%), renin-angiotensin system inhibitors (3.5%), antineoplastic agents (3%) and sedative/hypnotics (3%). Since 2005-2006, the proportions of ED visits for ADEs involving anticoagulants, antiplatelets, and diabetic agents have increased, whereas proportions involving antibiotics have decreased.
In children aged 5 years or younger, antibiotics were the most common drug class (56.4; 95% CI, 51.8-61). Among children and adolescents aged 6-19 years, antibiotics also were the most common class (31.8%; 95% CI, 28.7-34.9), followed by antipsychotics (4.5%; 95% CI, 3.3-5.6).
Among older adults, three drug classes recently targeted by federal patient safety initiatives (anticoagulants, diabetes agents, and opioid analgesics) were implicated in an estimated 59.9% (95% CI, 56.8-62.9) of ED visits. Four anticoagulants (warfarin, rivaroxaban, dabigatran, and enoxaparin) and five diabetes agents (insulin and four oral agents) were among the 15 most common drugs implicated. Medications to always avoid in older adults according to Beers criteria were implicated in 1.8% (95% CI, 1.5-2.1) of ED visits for adverse drug events.
Summary: The most common drug classes implicated in ED visits for ADEs in the United States are the same ones identified a decade ago – anticoagulants, antibiotics, diabetes agents, and opioid analgesics. The proportion of ED visits for ADEs involving anticoagulants has increased during the last decade with increased anticoagulant use. The prevalence of potentially inappropriate medication use in older patients also remains high.
Citation: JAMA. 2016;316(20):2115-25. doi:
Dr. Patel is a hospitalist in the division of hospital medicine and assistant professor of medicine at Cooper Medical School of Rowan University, Camden, N.J. He is CMSRU’s associate residency program director and serves as codirector of the Foundation of Medical Practice curriculum.