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Carolyn Thomas recently had a heart attack that was misdiagnosed. (Geoff Howe for The Globe and Mail/Geoff Howe for The Globe and Mail)
Carolyn Thomas recently had a heart attack that was misdiagnosed. (Geoff Howe for The Globe and Mail/Geoff Howe for The Globe and Mail)

When doctors make bad calls Add to ...

“You fit the demographic for gastric reflux,” he told her, and she went home feeling embarrassed.

The pain returned off and on for the next two weeks. “I consider myself a smart cookie,” Ms. Thomas says. “But a guy with the letters MD after his name had told me quite clearly it was not my heart. I had no intention of going back because I didn't want to make a fuss.”

Finally, the pain was too great – she could hardly walk 10 steps. This time, in the ER, the staff reacted quickly and a problem was flagged on her test results. When the cardiologist on call examined her, he performed a quick 30-second abdominojugular test, an old-school way of checking a vein for signs of a compromised heart . His diagnosis was conclusive: She had severe heart disease that required emergency surgery.

“How come I didn't have it two weeks ago?” she asked.

The cardiologist shrugged. “Sometimes, it is hard to pick up in women.”

In fact, research shows that women similar to Ms. Thomas are up to seven times more likely to be misdiagnosed. The symptoms of a heart attack in women often appear differently than in men, for whom much of the research has been done: As she points out, they're called widowmakers, not widower-makers. But that's too simple an answer. Likely, by the time the doctor had her normal test results (not uncommon in the early stages of a heart attack), he had already sized her up and committed several cognitive errors.

Most significantly, as in my husband's case, he quickly “anchored,” as psychologists call it, on the simplest, most common diagnosis. He had fallen into the trap of confirmation bias, mentally discarding the symptoms that didn't fit and piling up the bricks to support a false conclusion: In the exam room, Ms. Thomas would have presented as a trim and healthy professional with a large, Type-A personality and deadlines on her mind – the “demographic” of patient who might have stress-induced heartburn. Her test scores bolstered that first impression.

The doctor also may have considered, even unconsciously, the statistical likelihood of a heart attack, and his experience in treating previous cases. Perhaps he was tired after a long shift, or the hospital was full.

Psychologists have identified about 100 different cognitive traps people generally fall into – shortcuts to quick decisions that, once upon a time, probably saved us from being eaten. In a medical context, for example, doctors are susceptible to overconfidence bias (relying too much on intuition), diagnosis momentum (accepting a previous doctor's findings without enough skepticism) and availability bias (concluding that a new patient has the same problem as a recent patient with similar symptoms). Those mental miscues are even stronger when the correct diagnosis is a rare one.

Doctors also aren't immune to stereotypes. They may judge a patient on appearance, gender or race. They may be misled because someone has come in smelling like alcohol or is snappish in the examining room.

Dr. Croskerry poses this question: If doctors understood the psychology behind those errors, would they more on guard to watch for them? And if mistakes were put within the framework of cognitive science, as opposed to competence, would physicians be more willing to discuss them?

“You interact with people and those interactions colour your judgment,” he says. “What we would like doctors to do is detach themselves from the immediate pull of the situation.”

He gives this example: A sprightly 65-year-old woman came into a Halifax emergency department last summer. She was complaining about a hurt shoulder, saying she had strained it pushing the lawnmower. An X-ray was ordered, and she was sent home to rest. Days later, she returned, this time having a heart attack. “People had focused on her interpretations,” Dr. Croskerry says. They failed to consider the alternatives.

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