Misdiagnosis: the perils of “unwarranted certainty”

by Carolyn Thomas  ♥  @HeartSisters

Until being misdiagnosed with indigestion in mid-heart attack, I generally trusted that all people with the letters M.D. after their names knew what they were talking about when diagnosing serious medical problems. That was long before I tracked down a study(1) reported in the New England Journal of Medicine that women under the age of 55 who are experiencing a heart attack are seven times more likely to be misdiagnosed and sent home from the E.R. compared to their male counterparts presenting with identical symptoms.

And that’s why I now find Dr. Jerome Groopman’s landmark book, How Doctors Think, so illuminating.  It should be required reading for all med school students. 

Dr. Groopman believes that most cases of misguided medical care result from a cascade of cognitive errors on the part of a physician.  Physicians, he says, tend to go with their first impressions. 

   “Physicians, like everyone else, display certain psychological characteristics when they act in the face of uncertainty. There is the over-confident mindset: people convince themselves they are right because they usually are. And they tend to focus on positive data rather than negative data (for example, positive numbers seem to predict good outcomes). Such data have a powerful effect on our psyche, particularly in settings of uncertainty.

 “But biology, particularly human biology, is inherently variable. Those variations, at times very small and easily ignored, can prove important.”

“Specialists in particular, are known to demonstrate unwarranted clinical certainty. They have trained for so long that they begin too easily to rely on their vast knowledge and overlook the variability in human biology.

“Specialists are susceptible to diagnosis momentum: once an authoritative senior physician has fixed a label to the problem, it usually stays firmly attached because the specialist is usually right.”

This so-called “disregard for uncertainty” was what I faced with that Emergency Department physician who sent me home with a misdiagnosis of GERD (gastroesophageal reflux disease), despite the fact that I’d just presented with textbook heart attack symptoms like chest pain, nausea, sweating and pain radiating down my left arm. His emphatic but unwarranted clinical certainty:

“You’re in the right demographic for acid reflux!”

Unfortunately, physicians are still far more likely to be emphatically certain when facing their women patients compared to men.  And even if women can get past the E.R. gatekeepers before being sent home in mid-heart attack, studies consistently show that women heart patients are not only underdiagnosed, but also undertreated even when they are accurately diagnosed. (See: Gender Differences in Heart Attack Treatment Contribute to Women’s Higher Death Rates).

For example, a study(1) on 3,000 heart patients reported:

• men were 72% more likely to receive clot-busting drugs than women
• men were also 57% more likely to receive an angiogram, a process in which dye is injected into the arteries of the heart so that doctors can identify blockages through x-ray imaging
• men were 24% more likely to have angioplasty to reopen a blocked artery once identified via angiography
• the death rate among men was 48% lower during their hospital stay

Here’s another example: cardiologist Dr. Sharonne Hayes, founder of the Mayo Women’s Heart  Clinic, no longer routinely uses the term “rare” to describe heart attacks caused by the deadly condition known as Spontaneous Coronary Artery Dissection (SCAD), especially when discussing heart attacks in younger women. She reports, for example, that Mayo Clinic recently saw three cases in a single day –  one acute and two in outpatient consultation.

Instead, she now prefers to say that SCAD is an “underdiagnosed” cause of heart attack.

To help explain the phenomenon of unwarranted certainty, Dr. Groopman cites the work of Dr. Renee Fox, who has identified three basic types of physician uncertainty:

1. incomplete or imperfect mastery of available knowledge
2. limitations in current medical knowledge
3. difficulty in distinguishing between personal ignorance or ineptitude and the limitations of present medical knowledge

Dr. Fox observed hospital physicians struggling with uncertainty along with their numerous psychological mechanisms to cope with it, including black humour, making bets about who would be right, and engaging in some degree of magical thinking to maintain their poise and an aura of competence in front of the patients while making inaccurate diagnostic decisions or performing uncertain procedures.

Dr. Groopman’s book also reports on a study of interest to all of us heart patients, about physician accuracy in interpreting EKG results. To test their diagnostic skills, cardiologists in this study were given a number of EKG readings to assess them as follows:

• half of the x-ray films showed myocardial infarction (heart attack)
• 25% were normal
• 25% showed some other abnormality

The study’s results were disturbing. Even among specialists examining a routine test like an EKG, there were “widely divergent conclusions”.

For example, if you had a heart attack and went to Physician A, you would have a 20% chance that he would miss it.  If you had not had a heart attack and went to Physician B, there would be a 26% chance that he’d say that you did have one. EKGs can be variously interpreted by physicians.

Also disturbing was a study on the performance of radiologists done at Michigan State University by Dr. E. James Potchen. For example, when radiologists were shown a chest x-ray of a patient with a missing clavicle (collarbone), 60% of them failed to identify the missing clavicle. And when this group of radiologists were shown a series of chest x-rays that included duplicate films, their interpretations disagreed among each other an average of 20% of the time.  But even more interesting, when researchers showed them x-rays they had already interpreted, they disagreed with their own previous interpretations 10% of the time.

One of the most troubling aspects of Dr. Potchen’s study was the degree of certainty that the most accurate doctors had compared to the least accurate. He compared the top 20 radiologists studied (95% diagnostic accuracy) with the bottom 20 (75% accuracy) and found that the radiologists who performed poorly were not only inaccurate, they were also very confident that they were right when they were, in fact, quite wrong.

Another defense against uncertainty, Dr.Groopman explains, is the culture of conformity that begins in medical school. He quotes Dr. Jay Katz, a physician who teaches at Yale Law School:

“We were not encouraged to keep an open mind. We were educated for dogmatic certainty, for adopting one school of thought or another, and for playing the game according to the venerable but contradictory rules that institutions seek to impose on staff, students and patients.”

Doesn’t acknowledging uncertainty undermine a patient’s sense of hope and confidence in a physician and the proposed therapy?

Dr. Groopman writes that, paradoxically, taking uncertainty into account can actually enhance a physician’s therapeutic effectiveness:

“It can demonstrate the physician’s honesty, willingness to be more engaged with patients, commitment to the reality of the situation rather than resorting to half-truths, evasion and even lies. And it makes it easier for the doctor to change course if the first strategy fails, to keep trying.

“Uncertainty is sometimes essential for success.”

What can patients do when they truly believe it’s time to rethink a physician’s diagnosis?  Dr. Groopman recommends that you ask these questions of your doctor:

• “What else could it be?”  The cognitive mistakes that account for most misdiagnoses are not recognized by physicians; they largely reside below the level of conscious thinking. When you ask simply: “What else could it be?”, you help bring closer to the surface the reality of uncertainty in medicine.
• “Is there anything that doesn’t fit?”  This follow-up should further prompt the physician to pause and let his/her mind roam more broadly.
• “Is it possible I have more than one problem?”  Posing this question is another safeguard against one of the most common cognitive traps that all physicians fall into: search satisfaction. It should trigger the doctor to cast a wider net, to begin asking questions that have not yet been posed, to order more tests that might not have seemed necessary based on initial impressions.

Echoing Dr. Groopman’s advice, here also are five tools patients can use to make sure you get the right care, courtesy of Evan Falchuk over at Best Doctors Inc, a global health company founded by Harvard Medical School professors in 1989:

1. Don’t be shy. Be curious, and insistent. Ask your doctor questions about your diagnosis and treatment. Keep asking questions (like Dr. Groopman’s three suggestions) every step of the way until you’re satisfied with the answers.

2. Get a second – or third or fourth – opinion. But don’t show up and tell the next doctor: “I’ve been diagnosed with this type of illness, what do you think?” Instead, focus on telling the doctor all of your symptoms. Don’t guide his or her thinking toward what the first doctor said you have. As Dr. Groopman writes: “Telling the story again may help the physician register some clue that was, in fact, said the first time but was overlooked or thought unimportant.”

3. Take the time to get to know your family medical history – and make sure your doctor knows about it. Studies show your family history may tell you more about what kinds of illnesses you may have or are likely to get than even genetic testing.

4. Take someone with you to doctors’ visits. It’s hard to listen to difficult medical news and pay attention to all the details at the same time. Bring along a friend or family member to remind you of questions you want to ask, and to help you write down important notes.

5. Have your pathology rechecked. If you had a biopsy and your diagnosis is based on your pathology report, try to get it reviewed again. Pathology is incorrectly interpreted more often than commonly thought. If that interpretation is wrong, your diagnosis – and your treatment – are probably going to be wrong, too.

And I would add a sixth important suggestion to this list if you are sent home from Emergency, as I was, with a misdiagnosis that dismisses what you know is happening.

6. You know your body. You KNOW when something is just not right. KEEP GOING BACK! 

Imagine how you’d respond if the identical symptoms were happening to your daughter or your mother or your sister.  As one heart attack survivor I met at Mayo Clinic taught me to say (and as I now teach my women’s heart health presentation audiences):

“I don’t care what the tests say – SOMETHING is wrong with me!”

.

(1) Pope JH, Aufderheide TP, Ruthazer R, et al. Missed diagnoses of acute cardiac ischemia in the emergency department. N Engl J Med. 2000;342:1163-1170.

** American College of Cardiology’s 59th Annual Scientific Session, Atlanta, Georgia. March 14-16, 2010. Francois Schiele, MD, chief cardiologist, University Hospital of Besancon, France.

♥

NOTE FROM CAROLYN:  I wrote much more about the cardiac diagnostic gender gap in my book, A Woman’s Guide to Living with Heart Disease (Johns Hopkins University Press). You can ask for this book at your local bookshop (please support your neighbourhood independent booksellers!)  or order it online (paperback, hardcover or e-book) at Amazon – or order it directly from Johns Hopkins University Press (use their code HTWN to save 30% off the list price when you order).

Things Your Doctor May Not Know

Experts: Why So Wrong So Often?

How to Be a Good Patient

Seven Ways to Misdiagnose a Heart Attack

It Wasn’t Heart Disease – But What Was It?

What Doctors Really Think About Women Who Are ‘Medical Googlers’

Women’s Cardiac Care: is it Gender Difference – or Gender Bias?

Heart Attack Misdiagnosis in Women