More attention being paid to diagnosis errors

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When a patient visits his or her doctor, a certain level of trust is inherent in the interaction. Just as a consumer might expect an auto mechanic to diagnose the cause of an engine that stalls, or a stockbroker to surmise why certain stocks have been outperforming others, a patient trusts his or her physician to evaluate any symptoms and formulate a diagnosis that reflects the years of education and training the physician has received.

The human body is far more complex than a car, however, and arguably more complex than the stock market. Additionally, the many medical factors and and thinking and systemic processes that might lead a physician to a particular diagnosis are complicated in their own right. Because of this, diagnosis errors are gaining more attention from the medical field, the media, and patients.

When 310 physicians at 22 U.S. healthcare facilities were asked to anonymously confess the diagnostic errors they made or witnessed, the two most frequently listed conditions involved pulmonary embolism and adverse drug reactions, including overdoses and poisoning. Lung cancer diagnostic mistakes ranked a close third, followed by colorectal cancer, acute coronary syndrome, breast cancer, and stroke.

The doctors failed to order tests, neglected to report the results to their patients, or did not follow up when testing revealed abnormal findings.

Lab and radiology testing errors, including test ordering, test performance, and clinician processing, accounted for 44% of the missed diagnoses, which was the greatest share. Those surveyed cited descriptions of 583 diagnostic errors by primary care and specialist physicians.

Those are some of the conclusions of a report by Gordon Schiff, MD, associate director at the Center for Patient Safety Research and Practice at Brigham and Women’s Hospital in Boston, and colleagues at five other institutions. The authors describe the survey as one of “the largest reported case series of diagnostic errors to date and affords valuable insights into the types of errors that physicians are committing and witnessing.” The report was published in the November 9 Archives of Internal Medicine and received funding from the Agency for Health Research and Quality.

Additionally, according to a May 2008 American Journal of Medicine Article, “Overconfidence as a Cause of Diagnostic Error in Medicine,” errors in diagnosis cause as many as 5% of errors in perceptual specialties and 10%–15% of errors in other fields.

Such errors are often made because of a thinking failure, said Pat Croskerry, MD, PhD. Croskerry and Schiff spoke during a WIHI program in November 2009. WIHIs are talk show–style programs that the IHI produced in 2009 on various timely strategies for improving patient care.

“This doesn’t ever seem to be a feature of someone not trying hard enough,” said Croskerry, professor of emergency medicine at Dalhousie University in Halifax, Nova Scotia. “Historically, there has been a lot of confidence placed in physicians and their thinking abilities.”

In the field of cognitive psychology, there’s been a large focus on evaluating thinking failures. It’s a short step to apply that to medicine, where diagnosis is primarily a thinking business, said Croskerry.

However, diagnosis errors are both cognitive- and systems-based. Schiff and Croskerry helped plan the second annual Diagnostic Errors in Medicine meeting in October 2009, which ran in conjunction with the Society of Medical Decision Making’s annual meeting.

“These two worlds needed to come together, rather than being separate silos,” said Schiff regarding attempts to classify a diagnosis error as either a cognitive or a systems error.

Causes of diagnosis error

Although the notion of overconfident, arrogant physicians being the cause of diagnosis errors is not wholly incorrect, those qualities are not the sole reason that misdiagnoses are made, said Schiff. Other factors include spotty follow-up, time pressure, failure of physicians to share their uncertainties, malpractice fears, defensiveness, and inadequate feedback.

Schiff likened this last factor to a lawn sprinkler system that turns on automatically, regardless of whether it has rained that day. Instead of acting in a closed-loop system that provides feedback on whether diagnoses were right or wrong, physicians often work in an environment that does not allow for this follow-up or does not attempt to capture this feedback.

“What comes across as arrogance and carelessness is often a lot of constraints that physicians are working under,” said Schiff.

Additionally, understanding why people think in certain ways is key to understanding diagnosis errors, said Croskerry. By undoing certain biases in thinking, one might be able to think more clearly and perhaps come up with a more accurate diagnosis. But this task is easier said than done.

“The problem is it’s extremely difficult to de-bias people,” said Croskerry. “Generally speaking, trying to change the way that people think is a very challenging task.” He recommended addressing physician thinking biases in medical school, noting that the topic is currently overlooked at most institutions.

‘Not Yet Diagnosed’ may be better for patient

Another way of thinking that has become ingrained in most physicians is the idea that an overconfident, perhaps incorrect diagnosis is better than not diagnosing a patient at all.

Most patients don’t appreciate when their physicians seem indecisive about a diagnosis, and historically, physicians have been more successful when they confidently make a diagnosis, said Croskerry. Additionally, physicians validate their ability to make diagnoses when they appear confident.

“Physicians tend to place a lot of faith in their own diagnoses—most physicians think it’s the most important skill that they have,” said Croskerry. “It’s a lot easier, if you give the patient the wrong medication, to admit to something like that than to actually admit to your thinking processes having gone astray. People take that far more personally.”

Once a diagnosis is made, many other decisions concerning medical care are then made based on that diagnosis, said Croskerry. Further thinking about other possible diagnoses tends to stop. Assigning a “Not Yet Diagnosed” or “NYD” label to a patient whose symptoms don’t lead to a specific, certain diagnosis may ultimately help the physician ascertain the true cause of an illness by allowing more time to determine what the patient might have. Croskerry has seen success in Canada with this technique.

Schiff and Croskerry agreed that more emphasis should be placed on making physicians feel comfortable admitting uncertainty about a diagnosis to their patients, and that more education on this concept must be introduced at an earlier stage, perhaps in medical school. Additionally, Schiff said the issue of physicians admitting a diagnosis error is first and foremost about creating a patient safety culture.

“This idea about patient safety culture—creating a system where people can honestly look at errors in a blame-free way, learning from mistakes, and improving from those rather than covering them up or having to defend them—is so central for us learning,” said Schiff.

Technology: A double-edged sword

Technology has given medical professionals the ability to make better diagnostic decisions. Clinical decision support and electronic medical records are two places in which progress has been made, and more will likely be seen in the future. However, one disadvantage of computerized decision-making is its inability to read the context of a doctor-patient interaction, said Croskerry.

Medical testing is an area in which the ball is often dropped in regard to diagnoses, said Schiff. Instead of physicians making a diagnosis and ordering tests to confirm, the reverse often happens.

“We are now short-circuiting the diagnostic process and going right to diagnostic tests,” said Schiff. “The questions is, is this a step forward or a step backward? These are powerful new modalities to hopefully make us do better with diagnosis, but they also introduce all sorts of problems from ordering the right tests to harming people with these modalities [e.g., exposing patients to radiation from repeated x-rays].”

Schiff noted that it is important for physicians to ensure that they are using the tests properly, interpreting the results correctly, and following up with patients to measure whether the course of treatment based on a test was the best one.

Editor’s note: Find information on upcoming WIHI programs at To find the study published in the Archives of Internal Medicine, visit