In the U.S. each year almost 100,000 people above the age of 65 years are admitted to hospital because of emergencies caused by adverse drug events. According to the study, published in the New England Journal of Medicine by the Center of Disease Control and Prevention, of the thousands of medications available, it is a small group of blood thinners and diabetes medications that cause two-thirds of all emergency hospitalizations.

Dan Budnitz, M.D., M.P.H., director of CDC’s Medicaton Safety Program comments:

“These data suggest that focusing safety initiatives on a few medicines that commonly cause serious, measurable harms can improve care for many older Americans. Blood thinners and diabetes medicines often require blood testing and dosing changes, but these are critical medicines for older adults with certain medical conditions.

Doctors and patients should continue to use these medications but remember to work together to safely manage them.”

For their study, researchers obtained data from a nationally representative sample of 58 hospitals between 2007 and 2009. All data were from patients who took part in CDC’s National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project.

The researchers reported that nearly half (48.1%) of hospitalizations occurred amongst adults who were 80 years or above, whilst 65.7%, i.e. two-thirds of hospitalizations were caused by overdoses, or due to situations where patients may have followed the prescribed dosage but the drug reacted differently in these people.

Two-thirds of the emergency hospitalizations were due to four medications, either used alone or in combination:

  • 33,171 emergency hospitalizations (33%) were due to warfarin, a drug designed for the prevention of blood clots.
  • 14% of emergency hospitalizations were because of insulin, injections for controlling blood sugar levels in diabetics.
  • 13% percent were caused by antiplatelet drugs, such as aspirin and clopidogrel, drugs that prevent platelets or the formation of blood clots
  • 11% were due to oral diabetes medications (oral hypoglycemic agents)

The researchers identified particular medication safety issues that currently provide the most significant benefits in reducing patient harm and health care, and it is vital to continue national monitoring of adverse drug events with the approval of new medications that become more commonly used.

According to CDC researchers, drugs currently considered as being high-risk (1.2%) or potentially unsuitable (6.6%) for older patients by national quality measures were seldom identified as the cause of emergency hospitalizations.

Patrick Conway, M.D., M.Sc., chief medical officer of the Centers for Medicare & Medicaid Services and director of CMS’ Office of Clinical Standards and Quality says:

“Policies and improvement programs to promote safe use of medications that most commonly cause serious, measurable harms can increase patient safety and reduce unnecessary hospitalizations and costs at the same time.

We are working across the federal government to address common preventable adverse drug events through medication management, care transition programs, and other initiatives.”

Older people tend to require seven times more hospitalizations due to adverse drug events than younger patients. By the end of 2013, the Partnership for Patients initiative aims to decrease the number of preventable hospitalizations by 20%.

As Americans live longer, have higher rates of chronic conditions and take more medications, hospitalizations for adverse drug events are likely to increase. The Partnership for Patients’ main target of focus is to decrease adverse drug events, such as those that occur with blood thinners and diabetes medications.

For further information of CDCs actions to protect older adults from adverse drug events, please visit

Written by Petra Rattue