The Silence Surrounding Diagnostic Errors; Part II

Sometimes physicians are overly confident; sometimes they narrow their hypothesis too early in the diagnostic process. Sometimes they rely too heavily on advanced diagnostic tests and accept the results too quickly. As I explained in part one of this post, these are some of the reasons why physicians misdiagnose their patients up to 15 percent of the time. Of all medical errors, misdiagnosis is the one that we talk about least—in part, because we don’t know what to do about it, in part because most doctors have no way of knowing how many diagnostic errors they make.

“Complacency” (i.e. the attitude that “nobody’s perfect”) also is a factor, reports Drs. Eta S. Berner and Mark L. Graber in the May issue of the American Journal of Medicine. “Complacency reflects tolerance for errors, and the belief that errors are inevitable,” they write, “combined with little understanding of how commonplace diagnostic errors are. Frequently, the complacent physician may think that the problem exists, but not in his own practice...”

Autopsies

It is crucial to recognize that physicians are not simply deceiving themselves: in our fragmented health care system many honestly don’t know when they have mis-diagnosed a patient. No one tells them—including the patient.

Sometimes a patient who isn’t getting better simply leaves the doctor and finds someone else. His original doctor may well assume that he was finally cured. Or the patient may be discharged from the hospital, relapse three months later, and go to a different ER where he discovers that his symptoms have returned because he was, in fact, misdiagnosed. The doctors who cared for him at the first hospital have no way of knowing; they think they cured him. In other cases, the patient gets better despite the wrong diagnosis. (It is surprising how often bodies heal themselves.) Meanwhile, both doctor and patient assume that the diagnosis was right and that the treatment “worked.”

In still other cases, the patient dies, and because everyone assumes that the diagnosis was correct, it is listed as the “cause of death”—when in fact, another condition killed the patient.

When giving talks to groups of physicians on diagnostic errors, Graber says that he frequently “asks whether they have made a diagnostic error in the past year. Typically, only 1% admit to having made such a mistake.”

Here, we reach the heart of the problem: what Berner and Graber call “the remarkable discrepancy between the known prevalence of diagnostic error and physician perception of their own error rate.”  This gap “has not been formally quantified and is only indirectly discussed in the medical literature,” they note “but [it] lies at the crux of the diagnostic error puzzle, and explains in part why so little attention has been devoted to this problem.”

One cannot expect doctors to learn from their mistakes unless they have feedback: At one time, autopsies provided physicians with the information they needed. And the results were regularly discussed at “mortality and morbidity” conferences where doctors became Monday-morning quarterbacks, discussing what they could have done differently.

But today, “autopsies are done in 10 percent of all deaths; many hospitals do none,” notes Dr. Atul Gawande in Complications: A Surgeons Notes on an Imperfect Science. “This is a dramatic turnabout. Throughout much of the twentieth century, doctors diligently obtained autopsies in the majority of all death…Autopsies have long been viewed as a tool of discovery, one that has been used to identify the cause of tuberculosis, reveal how to treat appendicitis, and establish the existence of Alzheimer’s disease.

“So what accounts for the decline?” Gawande asks. “In truth, it’s not because families refuse—to judge from recent studies, they still grant their permission up to 80 percent of the time. Instead, doctors once so eager to perform autopsies that they stole bodies [from graves] have simply stopped asking.

“Some people ascribe this to shady motives,” Gawande continues. “It has been said that hospitals are trying to save money by avoiding autopsies, since insurers don’t pay for them, or that doctors avoid them in order to cover up evidence of malpractice. And yet,” he points out, “autopsies lost money and uncovered malpractice when they were popular, too.”

Gawande doesn’t believe that fear of malpractice has driven the decline in autopsies. Instead,” he writes, “I suspect, what discourages autopsies is medicine’s twenty-first-century, tall-in-the-saddle confidence.”

This is an important point. Autopsies have fallen out of fashion in recent years: “Between 1972 and 1995, the last year for which statistics are available, the rate fell from 19.1 percent of all deaths to 9.4 percent. A major reason for the decline over this period is that “imaging technologies such as CT scanning and ultrasound have enabled doctors to ‘see’ such obvious internal causes of death as tumors before the patient dies”, says Dr. Patrick Lantz, associate professor of pathology at Wake Forest University Baptist Medical Center. Nowadays an autopsy seems a waste of time and resources.

Gawande agrees: “Today we have MRI scans, ultra-sound, nuclear medicine, molecular testing, and much more. When somebody dies, we already know why. We don’t need an autopsy to find out…Or so I thought…” Gawande then goes on to tell the story of a autopsy that rocked him. He had completely misdiagnosed a patient.

What Autopsies Show

The autopsy has been described as “the most powerful tool in the history of medicine” and the “gold standard” for detecting diagnostic errors.  Indeed, Gawande points out that three studies done in 1998 and 1999 reveal that autopsies “turn up a major misdiagnosis in roughly 40 percent of all cases.”

A large review of autopsy studies concluded that “in about a third of the misdiagnoses the patients would have been expected to live if property treatment had been administered,” Gawande reports. “Dr. George Lundberg, a pathologist and former editor of the Journal of the American Medical Association, has done more than anyone to call attention to these figures. He points out the most surprising fact of all: the rate at which misdiagnosis is detected in autopsy studies have not improved since at least 1938.”

When Gawande first heard these numbers he couldn’t’ believe them. “With all of the recent advances in imaging and diagnostics . . . it’s hard to accept that we have failed to improve over time.” To see if this really could be true, he and other doctors at Harvard put together a simple study. They went back into their hospital records to see how often autopsies picked up missed diagnosis in 1960 and 1970, before the advent of CT, ultrasound, nuclear scanning and other technologies, and then in 1980, after those technologies became widely used.

Gawande reports the results of the study: “The researchers found no improvement. Regardless of the decade, physicians missed a quarter of fatal infections, a third of heart attacks and almost two-thirds of pulmonary emboli in their patients who died.”

But these numbers may exaggerate the rate of error. As Berner and Graber observe, “autopsy studies only provide the error rate in patients who die.” One can assume that the error rate is much lower in patients who survived. 

“For example, whereas autopsy studies suggest that fatal pulmonary embolism is misdiagnosed approximately 55% of the time, the misdiagnosis rate for all cases of pulmonary embolism is only 4%...” a large discrepancy also exists regarding the misdiagnosis rate for myocardial infarction: although autopsy data suggest roughly 20% of these events are missed, data from the clinical setting (patients presenting with chest pain or other relevant symptoms) indicate that only 2% to 4% are missed.”

Still, they acknowledge that when laymen are trained to pretend to be a patient suffering from specific symptoms, studies show that “internists missed the correct diagnosis 13% of the time. Other studies have found that physicians can even disagree with themselves when presented again with a case they have previously diagnosed.”

On the question of whether the diagnostic error rate has changed over time, Berner and Graber quote researchers who suggest that the near-constant rate of misdiagnosis found at autopsy over the years probably reflects two factors that offset each other:

1. diagnostic accuracy actually has improved over time (more knowledge, better tests, more skills);
2. but as the autopsy rate declines, there is a tendency to select only the more challenging clinical cases for autopsy, which then have a higher likelihood of diagnostic error. A long-term study of autopsies in Switzerland (where the autopsy rate has remained constant at 90%) supports the theory that the absolute rate of diagnostic errors is, as suggested, decreasing over time.

Nevertheless, nearly everyone agrees, the rate of diagnostic errors remains too high.

We need to revive the autopsy, Gawande argues. For “autopsies not only document the presence of diagnostic errors, they also provide an opportunity to learn from one's errors (errando discimus) if one takes advantage of the information.

“The rate of autopsy in the United States is not measured any more,” he observes, “but is widely assumed to be significantly <10%. To the extent that this important feedback mechanism is no longer a realistic option, clinicians have an increasingly distorted view of their own error rates.

“Autopsy literally means “to see for oneself,” Gawande observes, and despite our knowledge and technology, when we look we are often unprepared for what we find. Sometimes it turns out that we had missed a clue along the way or made a genuine mistake. Sometimes we turn out wrong despite doing everything right.

“Whether with living patients or dead, we cannot know until we look… But doctors are no longer asking such questions. Equally troubling, people seem happy to let us off the hook. In 1995, the United States National Center for Health Statistics stopped collecting autopsy statistics altogether. We can no longer even say how rare autopsies have become.”

If they are going to reflect on their mistakes, physicians need to “see for themselves.”

Comments

[Gregory D. Pawelski]

The median compensation for diagnostic radiologists is $419,148, according to a survey by the Medical Group Management Association.

[Gregory D. Pawelski]

When physicians practice, their record of experience may be called upon for 'proof' that they know what they are doing when they do any type of procedure. Placing a needle in hollow spaces. Sticking a scope in hollow spaces. Putting a catheter in a blood vessel. For surgeons, their credentialing requires 'proof' of numbers of surgeries.

Problems can occur when a battle of the 'turf wars' begins. Doctors fight when it comes to performing certain very lucrative procedures. When the interventional radiologist performs a procedure, it becomes more expensive than if it were done by the specialist who has been trained to do it easily.

Why should a patient get a lumbar puncture by an interventional radiologist who may use fluoroscopy, has a whole team of nurses and will likely bill out an extra ordinary facility fee for the use of all that great technology when the specialist, who learned that skill in their training, can do it quite quickly and comfortably at the bed side?

Although biopsies are the most intrusive method of tumor study, the procedures are able to detect a number of the maligancies missed by conventional methods of detection. Some advocate for other, less invasive methods like MRIs, ultrasounds and Pet Scans. However, if these procedures were to solely replace biopsies, many malignancies could be missed.

[Douglas Brunner, M.D.]

I would like to comment on Gregory Pawelski's suggestion that we need to remove more tissue, use larger needles, etc.

I am a diagnostic radiologist who has performed biopsies and other interventional procedures for many years. I strongly disagree with his suggestion. My philosophy has always been that the least invasive procedure that provides the needed diagnostic information is the right choice.

What Mr.?/Dr.? Pawelski does not consider is the difficulty of the procedure and the possibility of complications. All biopsies have the risk of complications - bleeding, pneumothorax (collapsed lung), etc.

These risks neede to be balanced against the usefulness of the information obtained and the difficulty of the procedure for the patient.

I am happy that I can provide an answer that allows for clinical decision making/treatment planning in the least invasive and difficult way possible.

[Douglas Brunner, M.D.]

I would like to comment on Gregory Pawelski's suggestion that we need to remove more tissue, use larger needles, etc.

I am a diagnostic radiologist who has performed biopsies and other interventional procedures for many years. I strongly disagree with his suggestion. My philosophy has always been that the least invasive procedure that provides the needed diagnostic information is the right choice.

What Mr.?/Dr.? Pawelski does not consider is the difficulty of the procedure and the possibility of complications. All biopsies have the risk of complications - bleeding, pneumothorax (collapsed lung), etc.

These risks neede to be balanced against the usefulness of the information obtained and the difficulty of the procedure for the patient.

I am happy that I can provide an answer that allows for clinical decision making/treatment planning in the least invasive and difficult way possible.

[maggiemahar]

Gregory, Chris, Doc 99 and Keith

Gregory and Chris: you both make a very good argument of the value of the work done by anatomic pathologists.

Chris--You wrote: "yes, it is humbling to attend the autopsy of one of your patients. Also humbling is the time-honored practice of attending your patients' funerals. I do it when I can. My physician father and grandfather would have been scandalized by physicians who did not do so when able to"

This seems to me spot on. You're not ignoring the fact that, in today's world, many doctors don't have time to do this. But when they can--it stikes me that this is the sort of thing that reinforces that bond of trust and respect between doctor and patient.

Doc 99-- It's probably always good when autopsies promote discussion. . . .

Keith--

I agree that it could be very, very hard to ask a family about an autopsy.

Perhaps doctors who are not comfortable doing this should ask palliative care specialists, hospital social workers, or others to ask the question?

The fact that diagnostic tests have gotten better doesn't really address the problem I was raising. Gawande points out that the doctor who makes the wrong diagnosis never orders the test that might have solved the mystery.

If you're looking for more recent research, consider what Dr. Jerome Groopman wrote in 2007 (his article includes research published in 2002):

"Croskerry became the head of the emergency department at Dartmouth General Hospital, and was struck by the number of errors made by doctors under his supervision.

"He kept lists of the errors, trying to group them into categories, and, in the mid-nineties, he began to publish articles in medical journals, borrowing insights from cognitive psychology to explain how doctors make clinical decisions—especially flawed ones—under the stressful conditions of the emergency room.

“Emergency physicians are required to make an unusually high number of decisions in the course of their work,” he wrote in “Achieving Quality in Clinical Decision Making: Cognitive Strategies and Detection of Bias,” an article published in Academic Emergency Medicine, in 2002.

These doctors’ decisions necessarily entail a great deal of uncertainty, Croskerry wrote, since, “for the most part, patients are not known and their illnesses are seen through only small windows of focus and time.” By calling physicians’ attention to common mistakes in medical judgment, he has helped to promote an emerging field in medicine: the study of how doctors think."

Gregory sent the lnk to this excellent article. You'll find it here: http://www.newyorker.com/reporting/2007/01/29/070129fa_fact_groopman?currentPage=all

[Doc99]

Autopsies? Heck, they're still fighting over JFK's autopsy.

[Keith Sarpolis]

Maggie,

The questions I would ask is whether most of these "missed diagnoses" were actually providing meaningful information or not. Patients who have serious illnesses for other reasons often have myocardial infarctions or pulmonary embolism as their health deteriorates. It is well recognised that pulmonary emboli are often found post mortem in such patients, which may or may not be the ultimate cause of death. While I respect the studies you quote, I would need to see more detail of what is considered a "preventable event". Just because one finds a pulmonary embolism at autopsy does not necesarily mean this was the ultimate cause of death.

Secondly, the autopsy figures you qote are from 10 years ago. In the realm of medicine, this is ancient history during which we have seen CT angiography supplant ventilation perfusion scans and high resolution imaging improving our diagnostic capabiities. It is not a fair comparison to use this outdated information. If such comparisons are not properly adjusted for biases in case selection, then the information is even less useful.

Having said this, it is not the nefarious idea that doctors still consider themselves gods on earth never capable of error (malpractice attorneys have clearly instructed us in the error of this thought and patients enabled by the world wide web constantly present with there own diagnosis and clearly impress upon us the inferior training we have undergone), but the uncomfortable idea of asking families at the time of a significant loss for such permission and the lack of interest in hospitals and pathology departments to perform these procedures.

[Maggie Mahar]

Keith--

While I believe anecdotes can add to our understanding (see my post on stats and stories) here I have to say that, despite
your experience, the reserach shows that families agree to autopsies 80 percent of the time, and despite the diagnostic tools that often
make doctors feel certain about the cause of death pre-mortem research done in 1998 to 1999 showed that if you did an autopsy, you found the diagnosis was wrong 40% of the time.

As reserachers point out, since autopsies are done so rarely these days, you have to assume that those 1998 to 1999 cases were particularly difficult cases--which is why an autopsy was done and why the rate of error so high.

But even looking at all cases, it seems diagnosis is wrong 3% or 4% of the time, and yet because doctors rely so heavily on diagnostic tools, they have a very hard time believing they made a mistake (see end of post.)

[Keith Sarpolis]

I do not think there is any silence regarding meidcal errors. The enviorment of medical practice is difficult given the consequences of openly admitting errors to patients. But a good physician realizes that erroers occur as part of being human and we cannot be 100% right all the time, especially when dealingwiththe complexity of medical care. Autopsies are performed less often since for the most part, we have diagnostic tools that often confirm what the cause of death is pre mortum. In the circumstance where a cause is unknown, it is always my suggestion to family that they consider autopsy arguing it is important for us to understand what the cause of death is to further our understanding as practitioners and for possibly significant family medical history. Most times family members decline.

[Atlantic Drugs]

Nice Information

[Gregory D. Pawelski]

I agree with Gawande's depiction of medicine's twenty-first-century, "tall-in-the-saddle" confidence (more like over-confidence).

We need to ensure that patients get the care they need and gather the evidence needed by physicians and patients to make informed decisions about treatment.

A medical oncologist on the one of the cancer information websites had stated that for years, physicians have settled on the smallest amount of tumor tissue possible, often with a fine needle aspirate that collects just a few cells.

We need to use larger bore needles to perform core biopsies or even remove entire lymph nodes, so that we can collect enough live "fresh" tissue to more reliably determine the histologic and molecular features of a cancer.

Like imaging technologies cannot substitute for the anatomic pathologist's thorough physical examination, imaging technology cannot substitute for the biologist's thorough examination of the features of a cancer cell.

[Chris Johnson]

Maggie:

To answer your question, I agree with Gawande that all the scans and tests have made autopsies, in the minds of many, quaint and obsolete. Yet my father-in-law, an anatomic pathologist for forty years, liked to point out that he did the most thorough physical examinations of any physician. There's no substitute for that.

And yes, it is humbling to attend the autopsy of one of your patients. Also humbling is the time-honored practice of attending your patients' funerals. I do it when I can. My physician father and grandfather would have been scandalized by physicians who did not do so when able to.

[maggiemahar]

Chris and Gregory--

Good to hear from you.

Chris--

The notion of attending your own patient's autopsy sounds like a very hard experience. But I can imagine that it could also be cathartic. Much like the family, the physician must have a driving "need to know" what really happened. . .

I'm guessing here-- is there any truth to my guess?

Why do you think the autopsy fell out of fashion?

Gregory--

You know far more about cancer and cancer reserach than I do, but I have read, in other places, that autopsies would be very useful in advancing the research . .

[Gregory D. Pawelski]

Another case where autopsies could be beneficial is in cancer clinical trials. Response rates (how much a tumor decreased in size) can be inflated when excluding patients who die during clinical trials (evaluable patients).

Patients not considered evaluable are often those who do not get the benefit of an entire treatment plan. The response rate is calculated after removing patients who died from the calculation. This inflates the response rate.

Clinical oncologists often want to publish papers for professional reasons. They need to report on the outcomes of their experiments, but if they had to wait for survival data it could take years until all the data was aggregated.

Response rates give clinical oncologists the opportunity to take a more optimistic look at therapies that have limited success. They can describe results as being complete remission, partial remission or simply clinical improvement.

If they treat all patients for three weeks, they can fairly evaluate the efficacy of a compound, which takes that long (on average) before it can be regarded as effective. If they disregard all patients who died after onset of therapy, and include only those treated three weeks or more, they can improve their data.

Autopsies of the deceased could reveal liver (or other organ) damage. Is this an effect of the drug?

Carcinomatous meningitis (CM) is clinically less common than brain metastasis, having dire consequences for both the quality of life and the overall survival of patients with solid tumors. It supposidly occurs in about 5% of all adult cancer patients, but autopsy studies may double this number, or more.

It is incumbent on the patient and the patient's professional caregivers to obtain all the information needed to make informed treatment decisions. Are they given that information by this type of cancer medicine?

[Chris Johnson]

Along with the reduction in autopsies comes the loss of another ancient custom--attending the autopsies of one's own patients. When I was in training (early 1970s) the entire team broke rounds to be present when an autopsy was done on one of our patients. Now that's seeing one's errors up close and personal.

The fundamental problem, of course, is that we don't know what an acceptable rate of diagnostic error is, or how to relate this to the spectrum of intrinsic diagnostic uncertainty ranging between such things as a gunshot wound to the abdomen and an insidious, obscure dementia.