Hospital Errors Occur 10 Times More Than Reported, Study Finds

Hospitals and U.S. regulators fail to record at least 90 percent of patient injuries, infections and other safety issues, a study found.

A review uncovered 354 so-called adverse events, such as pressure sores, bloodstream infections and medication errors, at three U.S. teaching hospitals. A system designed by the federal Agency for Healthcare Research and Quality identified 35 cases at the same facilities while the hospitals’ voluntary reporting programs found four, according to the study, published in the journal Health Affairs.

An incomplete picture of how often patients are harmed undermines public and private efforts to improve the quality of medical services in the U.S., David Classen, a professor at the University of Utah School of Medicine in Salt Lake City, and his co-authors conclude.

“Hospitals that use such methods alone to measure their overall performance on patient safety may be seriously misjudging actual performance,” the researchers wrote. “Reliance on such methods could produce misleading conclusions about safety in the U.S. health-care system and could misdirect patient-safety improvement efforts.”

Voluntary reporting by hospital operators and the U.S.- sanctioned method for tracking adverse events failed to provide accurate insights into the safety of U.S. hospitals, the study found. The report doesn’t disclose the names of the hospitals because of confidentiality agreements.

Adverse Events

Adverse events occurred during one-third of admissions at the hospitals, according to the researchers. Classen and his colleagues studied 795 patient records using the Cambridge, Massachusetts-based Institute for Healthcare Improvement’s Global Trigger Tool. The institute’s method involves reviews of patient charts by nurses, pharmacists and physicians. The researchers didn’t try to establish whether the harm could have been prevented.

The U.S. Agency for Healthcare Research and Quality’s Patient Safety Indicators uses administrative data collected by hospitals to detect medical errors. The Centers for Medicare and Medicaid Services uses these standards to evaluate safety at hospitals, the researchers wrote. Donald Berwick, the agency’s administrator, founded the Institute for Healthcare Improvement.

Efforts to track patient safety intensified after a 1999 report by the U.S. Institute of Medicine found that medical errors caused as many as 98,000 deaths and more than 1 million injuries each year.

Injured by Care

A six-year study of hospital admissions in North Carolina published in November in the New England Journal of Medicine found almost one in five patients were injured by their care.

Medical errors that caused harm to patients cost the U.S. $17.1 billion in 2008, according a review by the Seattle consulting firm Milliman Inc. of medical claims from 2001 through 2008 that also was published in the current issue of Health Affairs. Jill Van Den Bos, a Milliman health-care consultant, is the lead author.

The study identified about 564,000 injuries to patients admitted to U.S. hospitals and 1.8 million injuries to people using outpatient services. The most common and most expensive injuries were pressure sores and infections following surgery, Van Den Bos and her colleagues conclude.

To contact the reporters on this story: Jeffrey Young in Washington at

To contact the editor responsible for this story: Adriel Bettelheim at

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