Thursday, August 23, 2007

How Doctors THINK They Think...Book Review

"...many diagnoses are wrong, and that most medical errors are the result of cognitive biases resulting from quick and dirty rule-of-thumb heuristics we all use to make decisions when pressed for time, operating under uncertainty, or when we simply do not know a better decision rule. He tells us that doctors are often unaware of the impact such heuristics — and their accompanying biases — have on their diagnostic accuracy.

This is an excellent point, but it begs a simple question: What if the same cognitive biases that wreak havoc on doctors’ thinking — unawares — also influences their thinking about their thinking?1 In How Doctors Think, doctors tell us how simply spending more time with patients, asking open-ended rather than close-ended questions, reading “body language,” including patients’ emotions in the picture, etc., improves their diagnostic ability. How much impact do these factors have on diagnostic ability? Do they actually have any impact at all? These questions place Groopman’s book on shaky ground, for his evidence consists primarily of unrepresentative and mostly irrelevant testimonials in which doctors describe various atypical diagnostic adventures they’ve had, and how they think they either emerged victorious or dropped the ball.2 The problem is, this does not tell us anything about how doctors think, only how they think they think.

The problems get worse. Groopman tells us he is troubled that new doctors seem to be trained to “think like computers,” that they rely on diagnostic decision aids and some seductive “boiler-plate scheme” called evidence-based medicine. Groopman’s position, when his various arguments are gathered and assembled, becomes untenable. He admits doctors suffer from innumerable biases that diminish the accuracy of diagnosis, reducing many diagnoses to idiosyncratic responses fueled by mood, whether the patient is liked or disliked, advertisements recently seen, etc. Thus Groopman agrees with decision scientists’ diagnosis of doctor decision making; but then he goes on to wantonly dismiss what many of the very same researchers claim is the best (and perhaps only) remedy, the way to “debias” diagnosis: evidence-based medicine and the use of decision aids. In place of statistics what does Groopman suggest doctors rely on? Clinical intuition of course, the very source of the cognitive biases he pays lip service to throughout his book.

Unfortunately, what research Groopman cites to back his claims is somewhat one-sided and sometimes off the point. Two articles he cites both argue that decision aids pertaining to treatment (rather than diagnosis) don’t take into account when patients have multiple illnesses requiring multiple medications, which may interact with each other.3,4 This is an important point, but to attempt to argue from this single issue that decision aids shouldn’t be relied on is to make a rather specious generalization.

Most doctors do not like decision aids. They rob them of much of their power and prestige. Why go through medical school and accrue a six-figure debt if you’re simply going to use a computer to make diagnoses? One study famously showed that a successful predictive instrument for acute ischemic heart disease (which reduced the false positive rate from 71% to 0) was, after its use in randomized trials, all but discarded by doctors (only 2.8% of the sample continued to use it).5 It is no secret many doctors despise evidence-based medicine. It is impersonal “cookbook medicine.” It is “dehumanizing,” treating people like statistics. Patients do not like it either. They think less of doctors’ abilities who rely on such aids.6

The problem is that it is usually in patients’ best interest to be treated like a “statistic.” Doctors cannot outperform mechanical diagnoses because their own diagnoses are inconsistent. An algorithm guarantees the same input results in the same output, and whether one likes this or not, this maximizes accuracy. If the exact same information results in variable and individual output, error will increase. However, the psychological baggage associated with the use of statistics in medicine (doctors’ pride and patients’ insistence on “certainty”) makes this a difficult issue to overcome."

Cease and desist time.

Just as in all fields of endeavor there are some physicians who have a far better intuitive grasp of any given diagnosis. In other words, the knack.

As the quirks of aging bring me into the office of more and more medical doctors, it's easy to see that diagnosis and treatment regimens are an artform, and since not everyone can go to art class and emerge a Rembrandt, not every physician to-be can exit med school a veritable DeBakey in waiting.

And no, I do not believe aging to be a disease. But nowadays pretty much everything is, or at least labeled as such in order to write more prescriptions and keep the drug lords happy.

Kidding. Most of the docs I meet are genuinely concerned with doing the right thing as opposed to doing the lucrative thing. Some of them simply suck, and thats true in all walks of life.

No comments: