Medical errors leading to patient death are much higher than previously thought, and may be as high as 400,000 deaths a year, according to a new study in the Journal of Patient Safety.

The latest numbers are dramatically higher than those in the Institute of Medicine's 1999 report, To Err is Human: Building A Safer Health System, which estimated that up to 98,000 people a year die because of hospital mistakes. The data for that report is based on medical record reviews from 1984 and doesn't take into account studies published since 2008.

The new study reveals that each year preventable adverse events (PAEs) lead to the death of 210,000-400,000 patients who seek care at a hospital. Those figures would make medical errors the third leading cause of death behind heart disease and cancer, according to Centers for Disease Control and Prevention statistics.

The latest findings are based on research conducted by John T. James, Ph.D., who oversees the advocacy group Patient Safety America, an organization he founded in honor of his 19-year-old son who died in 2002 as the result of what he describes as negligent hospital care.

James analyzed four recent studies that used the "Global Trigger Tool" to flag specific evidence in medical errors, such as medication stop orders or abnormal laboratory results, which point to an adverse event that may have harmed a patient. A physician must concur on these adverse event findings before they classify the severity of patient harm. Based on the weighted average of the four studies, he concluded that at least 210,000 deaths are due to preventable harm in hospitals. But because of the limitations of the tool and incomplete medical records, he wrote that the number is likely twice that figure, more than 400,000 deaths each year.

"There was much debate after the IOM report about the accuracy of its estimates," James wrote in the study. "In a sense, it does not matter whether the deaths of 100,000, 200,000 or 400,000 Americans each year are associated with PAEs in hospitals. Any of the estimates demands assertive action on the part of providers, legislators and people who will one day become patients."

The problem, James said, is that action and progress on patient safety has been slow. He wrote that he hoped these latest evidence-based estimates of 400,000 patient deaths each year will foster an "outcry for overdue changes and increased vigilance in medical care to address the problem of harm to patients who come to a hospital seeking only to be healed."

Lucian Leape, M.D., who served on the committee that wrote the "To Err Is Human Report," told ProPublica that he believes James' estimate is accurate. He said the committee knew at the time of its 1999 study that the numbers were low.

"It was based on a rather crude method compared to what we do now," Leape told ProPublica. Furthermore, he said, medicine is more complex now, which leads to more mistakes.

For more information:

- read the study

- here's the ProPulica article

- see the 1999 IOM report

- here's the CDC statistics

- check out the Patient Safety America website

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