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More Than 1 Million Hospital Patients Experience Side Effects and Other Problems With Their Medications

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AHRQ News and Numbers

Release date: April 12, 2007

In 2004, 1.2 million hospitalized patients experienced an adverse drug event, 90 percent of which were due to a side effect from a medication that was properly administered, according to the latest News and Numbers summary from the Agency for Healthcare Research and Quality (AHRQ).

AHRQ also found that just 8.6 percent of adverse drug events among hospitalized patients were because they were given the wrong drug or the wrong dose in the hospital, or because they accidentally took an overdose or the wrong drug before entering the hospital. Other findings include:

  • Average total hospital costs for patients who experienced drug side effects or other adverse drug events were $10,100, compared with an average cost of $7,600 for patients who didn't experience adverse drug events.
  • The top three types of drugs involved in adverse drug events were corticosteroids, blood thinners, and anti-cancer drugs. The adverse drug events were mostly due to side effects from properly administered medications.
    • For corticosteroids, 11.6 percent of hospital stays involved an adverse drug event, but just 0.4 percent of those events were due to wrong drugs or doses.
    • For blood thinners, 9.4 percent of stays involved adverse drug events, 2.8 percent of which were due to wrong drugs or doses.
    • For anti-cancer drugs and drugs used to prevent organ transplant rejection, 9.6 percent of stays involved adverse drugs events, 0.4 percent of which were due to wrong drugs or doses.
  • Patients who suffered side effects from properly administered drugs tended to be older—an average of 64 years old—than those patients who suffered from problems related to wrongly administered medication—an average age of 47.
  • Nearly 60 percent of the patients who experienced an adverse drug event were women.

This AHRQ News & Numbers summary is based on data in Adverse Drug Events in U.S. Hospitals, 2004, HCUP Statistical Brief No. 29. The report uses statistics from the Nationwide Inpatient Sample, a database of hospital inpatient stays that is nationally representative of inpatient stays in all short-term, non-Federal hospitals. The data are drawn from hospitals that comprise 90 percent of all discharges in the United States and include all patients, regardless of insurance type, as well as the uninsured.

For more information, or to speak with an AHRQ data expert, contact Bob Isquith at or call (301) 427-1539.

Current as of April 2007


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