When 310 doctors 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, report the results to their patients or follow-up when testing revealed abnormal findings.
As it turns out, 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 included descriptions of 583 diagnostic errors by primary care and specialist physicians.
Those are some conclusions from 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." It was published in the Nov. 9 Archives of Internal Medicine, and received funding from the Agency for Healthcare Research and Quality.
Additionally, according to a May 2008 American Journal of Medicine article titled Overconfidence as a Cause of Diagnostic Error in Medicine, errors in diagnosis constitute as many as 5% of errors in perceptual specialties and 10% to 15% of errors in other fields. Often these errors are made because of a thinking failure, said Pat Croskerry, MD, PhD. Croskerry and Schiff spoke on an Institute for Healthcare Improvement’s WIHI program last week.
"This doesn't ever seem to be a feature of someone not trying hard enough," said Croskerry, professor in 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, which is in large part a thinking business, said Croskerry.
However, diagnosis errors are both cognitive- and systems-based. "These two worlds needed to come together, rather than being separate silos," said Schiff of trying to classify a diagnosis error as either a cognitive or a system error.
Causes of diagnosis error
While the notion of overconfident, arrogant physicians being the cause of diagnosis error is not wholly wrong, those qualities alone are certainly not the 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 the lawn sprinkler system that goes on automatically, regardless of whether it has rained that day. Instead of acting in a closed-loop system that provides feedback about whether diagnoses were right or wrong, often physicians 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.