The next patient safety target: misdiagnosis

Learn steps hospitalists can take to reduce error in their own practices and within their hospitals.

A 36-year-old woman recently presented with flu-like symptoms at Shonan Kamakura General Hospital in Kamakura, Japan. Just a week earlier, her son had been diagnosed with influenza, leading her doctors to think that might be the cause of her fever, fatigue, sore throat and dry cough.

But she tested negative for flu, so she was diagnosed with an upper respiratory infection, prescribed 1,200 mg of acetaminophen daily and sent home. The woman returned the next day, reporting symptoms of vertigo. Testing showed she had suddenly become anemic. Within days she was dead, felled by acute promyelocytic leukemia, which has a 5-year survival rate surpassing 70% when correctly diagnosed and treated.

The tragic case of delayed diagnosis, presented at the Diagnostic Error in Medicine 6th International Conference in Chicago in September, was one of those extremely rare “white zebras” that every physician dreads, expert diagnosticians said.

“These are tough cases at every level,” said David E. Newman-Toker, MD, PhD, associate professor of neurology and otolaryngology at Johns Hopkins University School of Medicine in Baltimore.

But new research shows that it's not just the one-in-a-million diagnoses that get missed, Dr. Newman-Toker noted. Diagnostic errors are responsible for more patient deaths, disabilities and medical liability costs than any other kind of medical mishap.

More than 100,000 U.S. medical liability cases over the past 3 decades involved diagnostic errors, according to a recent study by Dr. Newman-Toker and colleagues. These cases represented 29% of all those included in the U.S. National Practitioner Data Bank, making diagnostic mistakes the leading cause of medical liability claims, they reported in the August BMJ Quality & Safety. The average, inflation-adjusted payout in these cases was nearly $400,000—higher than for any other kind of medical mistake.

Other experts at the conference estimated that about 40,000 deaths a year in the U.S. are due to missed, delayed or wrong diagnoses and that misdiagnosis occurs as often as 10% of the time.

These alarming figures are grabbing the attention of some big players in health care, who soon will be pushing diagnostic errors, and initiatives to combat them, into the spotlight.

The Institute of Medicine (IOM) is “in the last stages of finalizing” preparations to convene a panel to examine and issue a report on the topic, said IOM spokeswoman Jennifer Walsh in an interview. Work could start as early as next year, pending a push for some additional financing, she added.

Meanwhile, The Joint Commission plans to make diagnostic-error reduction a patient safety priority.

“We know that there's a need,” said Daniel J. Castillo, MD, medical director of the commission's Division of Healthcare Quality Evaluation, during a talk at the conference, which was organized by the Society to Improve Diagnosis in Medicine (SIDM) and drew more than 230 attendees, mostly physicians.

“We at The Joint Commission and SIDM are starting to work together on ways in which our organizations can address this problem,” Dr. Castillo added. “It might be a National Patient Safety Goal, it might be a call for more research, or it might be performance measures.”

The growing focus on missed, delayed and wrong diagnoses is long past due and should be a top goal for hospitalists, said Robert M. Wachter, MD, FACP, who gave a keynote presentation at the conference.

“The safety and quality movement has been galloping along, but all the measures have to do with, “If the patient has diagnosis X, did you do thing Y?’” said Dr. Wachter, chief of the Division of Hospital Medicine at the University of California, San Francisco, in an interview. “But most of my training and most of what I do when I'm on the wards is make sure I get diagnosis X correct in the first place.”

Physicians' performance in this area is not being measured, he added. “There is always a limited amount of resources and attention in health care, and if it's all being focused on things that are less important than diagnostic acumen, then that gets less emphasis in training and in hospital programs,” Dr. Wachter said.

Most diagnostic mistakes cannot be traced to a single cause, research shows. System-related factors such as delayed or missed test results are involved in 65% of cases, according to a study published in the July 11, 2005 Archives of Internal Medicine. The same study found that cognitive errors made by physicians are involved in three-quarters of cases.

Hospitalists are well positioned to help improve diagnosis, experts at the conference said. Often, the initial diagnoses assigned to patients at admission turn out to be wrong. Sometimes that is because further testing has yielded new information that allows for more accurate diagnosis. But often it is because the admitting physician, whether outpatient or working in the emergency department, missed something, the experts noted.

One quality improvement project hospitalists can undertake is to track how often patients' principal diagnoses change from the time of admission to the time of discharge and use that information to provide feedback to the admitting physicians. Hospitalists also should track how often their own diagnoses turn out to be incorrect, suggested Robert L. Trowbridge, MD, FACP, a hospitalist and division director of general internal medicine at Maine Medical Center in Portland, in an interview.

“We need feedback on our diagnostic performance,” Dr. Trowbridge said. “Because of the way things go in hospitals, we don't always see whether the diagnoses we made were right or wrong. The same goes for our trainees, who may admit someone overnight, make the diagnosis and it turns out it was the wrong diagnosis and they never hear that that's the case.”

Maine Medical Center instituted an anonymous reporting system several years ago that allowed physicians to track diagnostic mistakes made by their colleagues. While that system is no longer in active use, it achieved the objective of raising awareness among doctors, Dr. Trowbridge said.

Now, morbidity and mortality conferences at Maine Medical Center frequently include discussions about the diagnostic process and factors such as cognitive bias, patient volume, time constraints or miscommunication that may have led to the adverse event under discussion.

Several well-regarded systems, popular among both experts and among practicing physicians, can be helpful in doing a differential diagnosis or getting quick, evidence-based advice at the point of care. These include UpToDate, Epocrates, DXplain, Isabel and ACP's Smart Medicine.

The ideal would be for these kinds of evidence-based diagnostic aids to be tightly integrated into electronic health records and build on the information already there, said Brent C. James, MD, chief quality officer and director of the Institute for Health Care Delivery Research at Intermountain Healthcare in Salt Lake City, who voiced optimism in his keynote presentation that such functionality is just around the corner.

“Within 5 to 10 years, [electronic health records] will be able to extract encoded data from about 90% of the information in the patient records,” said Dr. James. “And it will do it in such a way that it's clinically natural and not a burden on the clinicians. When that occurs ... it will have the potential to massively change diagnostic error rates.”