28 Jul Study investigates misdiagnosis
Diagnostic mistakes are the most frequent medical error as well as the most serious, according to
researchers from Johns Hopkins Medicine in Baltimore, MD.
Between 40,000 and 80,000 deaths in United States hospitals, each year might be related to
misdiagnosis, according to a new study.
Misdiagnosis may also play a role in 80,000–160,000 serious cases of harm to people's health
To see which conditions doctors are most likely to misdiagnose and which may lead to death or
disability, researchers analyzed over 11,000 cases from an extensive database of the U.S.
malpractice claims. The findings now appear in the journal Diagnosis.
We know that diagnostic errors happen across all areas of medicine," explains first study author
Dr. David Newman-Toker, Ph.D., director of the Johns Hopkins Armstrong Institute Center for
There are over 10,000 diseases," he goes on, each of which can manifest with a variety of
symptoms, so it can be daunting to think about how to even begin tackling diagnostic problems."
However, the team's technique aimed to do something different. They classified the conditions
according to a standard system, yet the grouping that followed was a new strategy.
There are dozens of different diagnoses &codes that all represent strokes. The same is true for
heart attacks and some of the other conditions as well, says Dr. Newman-Toker. These
differences often matter more for treatment than diagnosis."
To my knowledge," he explains, grouping these codes together to identify the most common
harms from diagnostic error had not been done before, but doing so gives us a &apples to apples'
comparison of the frequency of different diseases causing harms."
The team saw that a surprisingly small number of conditions" corresponded to the most
significant diagnostic errors.
Three types of the condition were responsible for nearly three-quarters of all serious harm" related
to misdiagnosis: infections, cancers, and vascular events. Combined, the researchers call these
the big three.
The scientists studied the severity and frequency of diagnostic errors in these conditions, along
with where these faults took place.
Over one-third of the errors leading to death or permanent disability were linked to cancers. This
figure reduced to 22% for vascular issues and 13.5% for infections.
Researchers broke down the big three" into 15 specific conditions, the misdiagnosis of which
often resulted in serious harm. Lung cancer, stroke, and sepsis came out on top.
The other 15 conditions included heart attacks, meningitis, pneumonia, blood clots in the legs
and lungs, and cancers of the skin, prostate, and breast.
Most errors occurred during an emergency situation or in an outpatient setting. Cancer-related
issues tended to occur in the latter location, while vascular and infection issues tended to occur in
These findings give us a road map for thinking about what kind of problems we need to solve in
which clinical settings," notes Dr. Newman-Toker.
The researchers' findings also showed the cause of most misdiagnoses: clinical judgment
failures. There are a number of ways to combat this, according to the team, including improving
teamwork skills and education, using technology to help with diagnosis, and giving people
quicker access to medical specialists.
However, the analysis did have a few limitations. The researchers remedied two of them — one
that suggested a bias toward malpractice claims that are easier to bring forward, such as cancer,
and the other being a dismissal of long term conditions that also cause serious harm.
The team corrected these biases by further analyzing previous studies that used data unrelated to
This strengthened the validity of the big three" findings but turned the tables to make vascular
events and infections the most prominent.
However, they could not fix some of the other limitations. They based their analysis on
malpractice cases rather than original medical records, which may have reduced accuracy and
maybe difficult to apply to the real world, where not all misdiagnoses result in a legal claim.
Future research could rectify this. In fact, Dr. Newman-Toker and his colleagues are planning to
continue focusing on misdiagnosis, eventually using a national dataset to estimate how many
people in the U.S. diagnostic mistakes detrimentally affect.
Before that, there will be a deeper dive into the big three." Specifically, the researchers wish to
examine the 15 conditions identified in the three categories, as well as how often doctors