Four drug classes cause most ADE admissions in elderly

March 15, 2012

The CDC found that just 4 classes of prescription drugs are responsible for more than two-thirds of drug-related hospitalizations in older patients.

"Of the thousands of drugs available to older adults, it is a really small group of medications that creates most of the hospitalizations," lead author Daniel Budnitz, MD, MPH, told Drug Topics. "These are medications that you really do need to pay attention to for appropriate dose and timing." Budnitz is director of the CDC's Medication Safety Program.

Only 1.2% of emergency hospitalizations for ADEs were attributable to HEDIS high-risk medications. Another 6.6% were associated with medications that are potentially inappropriate, according to the Beers criteria commonly used to evaluate medication safety in older adults.

"But in practice, we don't run into a lot of problems with Beers meds outside of digoxin, which has its own place on the CDC list."

The project, findings

The CDC findings came from an analysis of data collected by the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance (NEISS-CADES) project from 2007 to 2009. The project used a nationally representative probability sample of 58 nonpediatric hospitals that had at least 6 beds and a 24-hour emergency department (ED).

The results were not a complete surprise, Budnitz said. Anecdotal reports have long suggested that warfarin, insulin, oral anti-platelet agents, and oral hypoglycemics are important contributors to ADEs and hospitalizations. More surprising, he said, was finding that HEDIS high-risk medications and Beers-criteria medications produce fewer ADE hospitalizations than might be expected.

A total of 13 medications and classes of medications were implicated in at least 1% of ADE-related emergency hospitalizations in adults 65 and older. There were about 266,000 ADE-related ED visits annually and just under 100,000 hospitalizations yearly as a result of ADEs in older adults. Nearly half (48.1%) of all emergency hospitalizations for ADEs occurred in patients 80 years and older.

The other categories include opioid analgesics (4.8%), antibiotics (4.2%), digoxin (3.5%), antineoplastic agents (3.3%), antiadrenergic agents (2.9%), renin-angiotensin inhibitors (2.9%), sedative or hypnotic agents (2.5%), anticonvulsants (1.7%), and diuretics (1.1%).

"These results, 4 medications responsible for two-thirds of emergency hospitalizations, aren't a surprise at all to us," said Mike Cohen, RPh, MS, president of the Institute for Safe Medication Practices (ISMP). "We have had an ambulatory care high-alert drug list since the 1980s and most of these drugs are already on it. If you focus on just this small area with your patient education and patient safety efforts, you improve safety dramatically. I'm glad CDC started this database. It's great support for the concept of high-alert drugs."

Effective education needed

A second key point, Cohen noted, was that two-thirds of hospitalizations were due to accidental overdose. That suggests the toll of ADEs and hospitalizations could be reduced with more effective education for patients and their caregivers.

ISMP is also studying mandatory counseling for high-alert drugs in the community setting under a grant from the Agency for Health Care Research and Quality. ISMP has developed a series of counseling checklists for pharmacists and easy-to-understand patient information materials that can help.

"This study tells me that we have a real opportunity to make a difference in outcomes with these patients and these drugs," Garrett said. "It points up the importance of following up with these patients. All of us have a responsibility and an opportunity to really laser in and make a difference."