New study finds up to ten times more hospital errors than other methods have detected

Despite a focus on patient safety, large risks, high costs, and gaps in health care quality persist, according to April Health Affairs


Bethesda, MD — Despite more than a decade of national focus on patient safety, medical errors and other adverse events occur in one-third of hospital admissions—as much as ten times more than some previous estimates have indicated, according to authors of a new study in the April issue of Health Affairs.

The study is one of several articles in this month’s Health Affairs that address persistent challenges facing the US health care system with respect to closing the gaps in quality and safety of care—challenges identified as far back as 2001 by the Institute of Medicine’s landmark report, Crossing the Quality Chasm. This thematic issue of the journal also looks at the profound costs incurred by shortfalls in quality; the optimal ways to measure quality; and the most successful ways to date of improving the quality of care. Taken together, the Health Affairs papers portray a mixed picture of health care quality in the United States. The Robert Wood Johnson Foundation, the nation’s largest philanthropy focused solely on health and health care, sponsored the issue.

“Without doubt, we’ve seen improvements in health care over the past decade, and even pockets of excellence, but overall progress has been agonizingly slow,” said Health Affairs Editor-in-Chief Susan Dentzer. “It’s clear that we still have a great deal of work to do in order to achieve a health care system that is consistently high-quality—that is, safe, effective, patient-centered, efficient, timely, and devoid of disparities based on race or ethnicity.”

The patient safety study, conducted by David C. Classen of the University of Utah and coauthors at the Institute for Healthcare Improvement, compared three methods for detecting adverse events in hospitalized patients, including the Institute’s own Global Trigger Tool. The study drew on comparable samples of patients from three leading hospitals that had undertaken quality and safety improvement efforts.

Among the 795 patient records reviewed, voluntary reporting detected four events, the Agency for Healthcare Research and Quality (AHRQ) Indicators detected 35, and the Global Trigger Tool detected 354 events, ten times more than the AHRQ method. In other words, the AHRQ indicators and voluntary reporting missed more than 90 percent of adverse events identified by the Global Trigger Tool. If anything, the researchers say, their findings are conservative, because they rely on medical record review, which would not detect as many adverse events as direct, real-time observation would.

The researchers say that reliance on voluntary hospital reporting or the AHRQ indicators could lead to seriously flawed perceptions of patient safety in the United States. They also note that the Global Trigger Tool detected a much higher rate of adverse events for hospitalized patients than previous studies have shown. Although the Global Trigger Tool is a somewhat more resource-intensive method because it involves medical record review, the researchers suggest that it could be incorporated into commercial electronic health record systems, thus making it easier and less costly to use.