Errors in the report on medical errors?

The Institute of Medicine (IOM) report on medical errors that caused such a stir was full of its own errors, according to a new analysis. The IOM report overstated the degree to which the medical errors shortened patients’ lives, says Rodney A. Hayward, MD, a co-author of the new study and a researcher with the Department of Veterans Affairs Center for Practice Management and Outcomes Research in Ann Arbor, MI (JAMA 2001; 286:415-420).

Eye of the beholder

In Hayward’s study, "Preventability is in the Eye of the Reviewer," he studied the implications of a death described as "preventable by better care" in terms of the probability of immediate and short-term survival if care had been optimal, with 14 board-certified internists assessing the conclusions made by previous researchers. They studied 383 reviews of 111 hospital deaths at seven Department of Veterans Affairs medical centers around the country.

The internists determined that almost one-quarter of patient deaths were rated as at least possibly preventable by optimal care, with 6% rated as probably or definitely preventable. The reviewers’ estimates of the percentage of patients who would have left the hospital alive had optimal care been provided was 6%. But after considering three-month prognosis and adjusting for the variability and skewness of reviewers’ ratings, the clinicians estimated that only 0.5% of patients who died would have lived three months or more in good cognitive health if care had been optimal, representing roughly one patient per 10,000 admissions.

By contrast, the IOM report estimated that medical errors kill at least 44,000 people in U.S. hospitals each year, and possibly as many as 98,000. In hospitals alone, the IOM estimated that 7,000 die each year from medical errors. Hayward says that figure is probably too high because many of the patients would not have lived any longer if the error had not occurred.

The authors concluded that "previous interpretations of medical error statistics are probably misleading."