Experts lambast study on medical error-related deaths

Topics: Research and Development, Providers

By Sam Bernstein, staff writer

A study in BMJ concluding that medical errors are the third-leading cause of death in the United States is coming under scrutiny from some experts who say the research is weaker than it appears.

As American Health Line and other media outlets reported earlier this month, researchers at the Johns Hopkins University School of Medicine reviewed four major studies conducted between 2000 and 2008. They found that medical errors cause about 9.5 percent of all deaths in the United States, or about 250,000 deaths annually.

That would make medical errors the country's third-leading cause of death, behind heart disease and cancer, which each caused about 600,000 deaths in the United States in 2014.

Scrutiny of methodology

But Vinay Prasad, a senior scholar at the Center for Ethics in Health Care at Oregon Health & Science University, argued that there are problems both with the study's methodology and with how it framed its findings.

In a STAT News opinion piece, Prasad wrote that to reach the estimated number of deaths cited in the paper, "the authors essentially averaged error-related death rates from four prior studies and then extrapolated it to the number of hospitalized patients today." While acknowledging that approach has merit, Prasad raised concerns that, because the study did not review current patient records, its estimates "may be wrong by a large magnitude."

Further, Prasad said the study avoids asking hard questions about what is -- and is not -- a medical error. The study authors define a medical error as any action "that does not achieve its intended outcome" or has the potential to harm a patient. But that definition "is uselessly broad," Prasad argued.

A better definition, he said, would focus on actions that cause harm -- although even then, many errors "exist in a gray zone."

What if, Prasad posited, a doctor delays sending a patient to the intensive care unit (ICU) who later dies? "Would she have died had she been transferred to the ICU 45 minutes sooner?" he asked. It's a tough question to answer, but Prasad argued that the BMJ study falters by not engaging with such complex questions.

"When the public hears a statistic like '251,454 deaths,' they get the impression that these are people whose names you could put on a wall," Prasad wrote. "But that's not the case at all."

Other critics agree that the numbers may be misleading. A "Skeptical Scalpel" blog post questioned the approach used to extrapolate the number of annual medical error-related deaths and the researchers' claim that "'some argue that all iatrogenic deaths are preventable.'"

The blogger -- a former chair of surgery and residency program director who writes anonymously on the blog -- noted, "I disagree. I have analyzed other papers on this subject and pointed out that certain complications and deaths are not 100 percent preventable." For instance, "Skeptical Scalpel" wrote that "some patients will suffer myocardial infarctions and die even when they are properly treated."

Meanwhile, radiologist Saurabh Jha argued in "The Health Care Blog" that the findings amount to hyperbole, which "creates resentment in patients who have been harmed" and "tunes out doctors because the comparisons are so egregious that they become parody."

He added, "Medical errors lose gravity precisely because overzealous safety advocates elevate them to a frightening level of quantitative seriousness."

The big picture

But the paper's authors and critics may not be quite as far apart as they seem.

The study noted that "although the assumptions made in extrapolating study data to the broader U.S. population may limit the accuracy of our figure, the absence of national data highlights the need for systematic measurement of the problem."

That's why the BMJ authors called for more systematic measurement of medical errors, such as dedicating a space on death certificates to acknowledge deaths resulting from medical errors.

But that call, which the medical journal in response to critics said was the "key argument" of the paper, may have gotten lost behind its attention-grabbing numbers.