Medicine Is Not An Exact Science (Countering A Defensive Medicine Myth)
As I’ve argued on this blog before, “defensive medicine” — i.e., the claim that doctors routinely order useless medical tests and procedures solely to prevent the appearance of malpractice — is a myth. By and large, if a test or procedure won’t help prevent the patient from developing a serious complication, then it won’t help the doctor avoid a lawsuit if something goes wrong. Conversely, if a test or procedure would have helped the patient avoid a serious injury or complication, then, typically, the standard of medical care required the test or procedure anyway. Tort liability arises only when a doctor fails to do what a reasonable doctor would do and that failure causes the patient harm.
As I detailed again back in August, states that enacted draconian “tort reform” laws — which made it impossible for injured patients to pursue all but the most egregious cases of malpractice involving millions of dollars in damages — have not seen any reductions in their health care costs. Tort law and malpractice lawsuits simply don’t have much of an effect on health care and health care spending in the United States. That’s not surprising, considering that malpractice payments comprise a mere one-tenth of 1 percent (0.11 percent) of national health care costs. Plenty of unnecessary medical procedures are performed every day, but the motive for them is the obvious one: to make money.
However, the myth of defensive medicine just won’t go away, and on Christmas Day, a doctor under the pseudonym “Skeptical Scalpel, MD” posted that “defensive medicine is ubiquitous and not going to go away soon. Health care costs will continue to rise.” He recommends “a massive culture shift” among doctors and patients.
It’s unclear what kind of culture shift Dr. Scalpel has in mind, but the three examples of “defensive medicine” he gives suggest he wants doctors to scrap the differential diagnosis (the process of elimination that forms the backbone of clinical medicine) and stop reaching out to colleagues for advice on complicated cases.
Here’s his first example:
A young man with chest pain arrives in the ED. After taking a history and examining the patient, the ED MD is 99.99% certain that the patient did not have a heart attack or a pulmonary embolism. But he’s a little short of breath. He remembers a case of a fatal PE with only minimal shortness of breath, orders a blood gas and CT angiogram of the chest.
Any physician who is “99.99% certain” that patient did not suffer a heart attack is unfit to practice medicine. A patient history and physical examination will never give any physician enough information to be “99.99%” or 98.78% or 73.64% or 22.13% or 00.01% certain of anything. Clinical medicine doesn’t work that way. A doctor in that circumstance might reasonably be “pretty sure” or “confident” that the patient isn’t having a serious, urgent medical condition, but to ascribe any specific probability to it — much less a probability (“99.99%”) that is an incredible 3.89 standard deviations from the mean, with an equally surprising zero confidence interval — means that the doctor has utterly failed to understand the limits of a clinical medicine, and has wrongly presumed a level of mathematical precision to their analysis.
I’m sure Dr. Scalpel meant “99.99%” as an informal shorthand for “pretty sure.” But there’s a reason he did it: because replacing his “99.99%” with “pretty sure” makes the example far less persuasive. It sounds a lot better to claim some doctor’s gut-level intuition is actually a medical fact asserted with “99.99% certainty,” but it’s dead wrong, and it reflects a serious problem with the doctor’s mindset.
Truth is, the doctor in that example has committed malpractice because they have not applied the differential diagnosis, which requires ruling out the most serious conditions. Doctors in clinical settings aren’t supposed to vaguely speculate about probabilities, they’re supposed to start with the worst that could happen and then work their way down. If a doctor can, without harming the patient, obtain more information that can help them rule out a serious condition, then they must do so.
In this case, it’s a young man (presumably a fit one, without any significant comorbidities) who had chest pain significant enough to send them to the ER, and with a little shortness of breath. He could indeed be suffering a heart attack. So what to do? Crack open their chest and go for a transplant?
Of course not. I don’t know why Dr. Scalpel says the next step is to “order[ ] a blood gas and CT angiogram of the chest.” From a malpractice lawyer’s perspective, what I’d look for as the next step would most likely be an electrocardiogram (as the Mayo Clinic says, “This is the first test done to diagnose a heart attack.”). Then normal blood labs would likely be drawn and reviewed, potentially including an arterial blood gas (though unlikely, given the minimal shortness of breath; the patient might instead get a pulseox). If those showed problems as well, an echocardiogram would be done, and, lastly, and typically only after the other tests have shown anomalies, would an angiogram be done.
And what would be so wrong about that? Is is such a terrible burden on the health care system to run an electrocardiogram and normal blood labs on a person with substantial enough chest pain and shortness of breath that they brought themselves to an ER? The cost of each is trivial, and the risks are non-existent. Dr. Scalpel is advocating for the equivalent of a mechanic saying, “I don’t need to look” when your brake light comes on because the mechanic is “pretty sure” it’s just the sensor. Odds are, they’re right — but you don’t go to a mechanic or a doctor to play Russian roulette (where, odds are, you’ll be fine). “Pretty sure” just won’t cut it in matters of life and death.
Dr. Scalpel’s other two examples are even worse: a young girl with lower abdominal pain gets an ultrasound for appendicitis (among the least invasive, least expensive, and most helpful tests in history — remember this funny GE ad for their portable ultrasound?), and a surgeon calls up an infectious disease colleague to confirm he or she can drain an E. Coli-infected post-operative wound by draining it, without antibiotics.
Is that the big boogey-man of defensive medicine? Two patients who might really have life-threatening conditions receive cheap, non-invasive tests, and a third patient with a dangerous complication gets a quick informal consultation from an expert? If we’re really at that level of penny-pinching in our healthcare system, then there are plenty of other places to look for waste — like in the trillion dollars in damage caused every year by malpractice.
[UPDATE: Skeptical Scalpel has posted a reply, with the rather curious argument that all of the testing he believes is the standard of care is actually worthless, and with a couple more assumed tests lumped on the examples.
On the first example, he asserts that a CT angiogram is performed every time a patient has chest pain, which, as I explained, simply isn't correct: a whole battery of non-invasive, inexpensive tests are performed first, with the CT angiogram following worrisome results on those tests.
On the second example, he now argues the ultrasound is worthless in ruling out appendicitis. If that's correct, then the ultrasound makes no difference one way or another in terms of the doctor's liability; however, the very source he cites for that claim concludes "Bedside ultrasound is helpful in patients with suspected appendicitis to confirm the diagnosis." Recognizing that, he then lumps on the assumption that the patient will also be given a CT, for unexplained reasons.
On the third example, he notes (correctly) that surgeons have far more experience in treating post-operative wounds than infectious disease specialists — one of the reasons why his example didn't make sense in the first place — and then notes (again, correctly) that the infectious disease specialist would likely refuse to sign off on the surgeon's routine patient without actually accepting the patient as their own.
It's important to bear in mind what we're talking about here. I think doctors by and large try to do right by their patients, ordering the tests they think will rule out serious conditions. Skeptical Scalpel, however, thinks that a significant portion of the medicine practiced in this country is useless, and done solely to avoid liability, and the three best examples he can come up with are debatable (the ultrasound for suspected appendicitis), meaningless (the post-operative ID consult that usually won't happen and which won't change the surgeon's liability anyway) or simply wrong (the young man with chest pain automatically receiving a CT angiogram).]