Friday, August 03, 2012

Defensive Medicine and Fear vs. Reality

Robert Samuelson describes the hypothesized fear that some claim causes doctors to prescribe unnecessary (and sometimes potentially harmful) tests to avoid a potential malpractice claim,
The [journal Health Affairs] argues that rapid growth [in health spending] was driven partly by powerful non-medical forces: Demanding patients insisted on scans; doctors feared malpractice suits if they refused; and doctors and hospitals wanted to maximize revenues. What explains slower growth is that these incentives weakened....

One change was the adoption of prior authorization by many private insurers. Doctors usually had to get permission for advanced imaging and, if patients’ conditions didn’t comply with guidelines, explain why. This may have discouraged referrals, because doctors don’t like being overruled. Patients also became less demanding, because deductibles and co-payments rose.
Yet despite less of this expensive testing in cases where it's not needed or where the need is borderline, there has been no increase in malpractice litigation. To the contrary, the number of malpractice lawsuits continues to drop.

The leading problem with the argument that unnecessary imaging studies were driven by fear of malpractice litigation is that a doctor can only be held liable for malpractice if he violates the governing standard of medical care - a standard defined by doctors, not by lawyers. The conceit is that the additional test might reveal something that did not show up in prior tests, saving the doctor from a "failure to diagnose" claim, but even without the test if the doctor established that he adhered to the governing standard of care the claim would not succeed.

Under the former model implied by Samuelson, the doctor meets with the patient, the doctor either says "This really expensive imaging study is unnecessary and won't help me diagnose your problem," or makes a statement he knows to be misleading, "We need this really expensive test to verify your diagnosis", the patient responds, "I want it anyway", and the doctor goes along with the patient's request.

The first explanation offered for the drop in testing, that insurance companies became more likely to require prior approval and "doctors don’t like being overruled" undermines the notion that fear of malpractice litigation is a significant factor. It is difficult to believe that a doctor who is willing to order medically unnecessary tests on large numbers of patients in order to avoid the tiny chance that one will later file a frivolous lawsuit against him is going to have such a dramatic change of heart, "I'm not even going to mention the additional test because the patient might want it, and then the insurance company might say 'no'."

Further, Samuelson informs us, "Data from one insurance group suggested that about half the MRI slowdown involved lower back, elbow and knee pain." (The article Samuelson references also mentions low-value MRI's of the pelvis.) Lower back pain can be associated with serious medical conditions, but the study distinguishes MRI's "used to diagnose lower back pain" from those ordered when a patient is "considering surgery or physicians strongly suspected systemic disease". But leaving the lower back aside, it's difficult to believe that doctors are ordering large numbers of knee and elbow MRI's as "defensive medicine".

More than that, its unlikely that the doctor is going to know what any given insurance company will or will not approve before his office checks the policy terms and, if necessary, makes the request. It's even less likely that it will be the doctor making the call. Why would a doctor fret if an insurance company says "no" to one of his clerical staff? If the doctor believes that the test is medically necessary, he is likely to fight the insurance company. I've dealt with medical clinics who have a full-time employee whose only job is to push back against insurance companies' efforts to deny or limit care.

The second explanation, speculation that "Patients also became less demanding", seems like a big stretch. If a test is medically necessary, the doctor is going to push the patient to get the test despite the out-of-pocket cost. If your doctor tells you, "You need a $5,000 medical test in order for me to diagnose your condition," even if you're one of the "27 percent" of "workers with deductibles exceeding $1,000", odds are you're going to bite the bullet. Odds are you'll be billed after-the-fact, and you only pay a deductible once. If you're looking at very expensive medical testing odds are that you have an underlying medical condition that is going to take you across that line, anyway.

The concept of "defensive medicine" Samuelson implies would also presuppose a highly informed patient. They see the doctor for diagnosis and treatment. The doctor provides care he believes is appropriate. They then ask, "Shouldn't we also use the [specific expensive medical test or imaging study]?" The reality is, confronted with a non-specific diagnosis or statement by the doctor about a low-probability but high consequence possibility in a differential diagnosis, the patient is likely to ask, "Isn't there anything else we can do," with the doctor identifying the additional test that could be performed.

It's difficult to see how the "defensive medicine" line would have changed. It's unlikely that the doctor who is inclined to order unnecessary testing is fretting, "Oh no, if I mention the test there's a one in four chance that they have a high copay and they might refuse it," or "Oh no, if I mention the test they may have insurance that requires pre-authorization and the request may be denied." If they don't mention the test to the patient they're right where they would be without "practicing defensive medicine" - they can still be accused of not mentioning or ordering the test. If they recommend the test and don't push the patient to fight an insurance company denial or to pay the copay, they are similarly exposed.

If the assumption is that certain doctors will liberally prescribe medically unnecessary tests only if they don't expect to encounter friction - only if they expect an insurance approval, and only if they believe that the patient's contribution to the cost of the test will both be known to the patient in advance and not scare off the patient - then "defensive medicine" really translates into, "I'll order whatever testing I think the insurance company will pay for." There's a madness to that method, as there's always one more test you could order and, frankly, the patients with the best insurance likely fall within the population that is least likely to sue.

It could be hypothesized that the economic changes have forced a learning process on the part of doctors - that frivolous malpractice lawsuits are so rare, ordering unnecessary medical testing has no meaningful impact on whether or not any given doctor gets sued. But then, as Samuelson notes, there's the elephant in the room:
Finally, some reimbursement rates fell. In 2005, Congress mandated that Medicare couldn’t pay free-standing imaging centers — often owned by doctors — more than it paid hospitals for outpatient imaging. This “reduced profits for imaging centers and resulted in extensive consolidation in the industry,” the study said. Under complex reimbursement rules, doctors had incentives to establish imaging centers or install scanning devices in their offices, says Levy. And these imaging centers seemed “particularly active in stimulating demand.”
That is, it appears that the leading cause of unnecessary medical imaging, performed at the highest cost, was physician self-referral - sending patients to receive tests at centers owned in whole or in part by the doctor making the referral, with the referring doctor having both the need to keep his imaging center busy and receiving a share of its profits. No, I'm not going to argue that this was a standard practice across the board, and even within the context of self-referral I'll give the majority of doctors the benefit of the doubt, that they referred patients to their own clinics for tests they would have ordered anyway - the difference being much more one of where the test is performed than whether it is ordered. But self-referral has long been identified as one of the leading causes of unnecessary medical testing, a genuine, documented cause of medical inflation.

It is easy to understand why a doctor does not want to be accused of malpractice under any circumstances, and why a doctor would want to avoid being sued even in a context in which he will easily defeat the suit in the early stages of litigation. People who argue that "defensive medicine" plays a large role in the cost of medicine ignore the fact that to the extent that "defensive medicine" exists, it is largely driven by emotion. Were "defensive medicine" is driven by facts, you would expect to see a reduction in low-value medical testing when the rate of malpractice lawsuits drops. Yet the prevalence of low-value testing and the cost of medical care is not correlated to the number of malpractice lawsuits. If doctors believed that certain expensive tests were necessary to avoid potential lawsuits, even if not medically necessary, you would see them pushing patients to pay for the tests and fighting insurance companies to gain approval. Instead you see them deferring to insurance companies or, it would seem, not even mentioning to patients tests that might stretch the patients' pocketbooks.

What you do see through studies such as the one Samuelson describes is that you can reduce the number of low-value tests across the board by changing the economic environment for such testing. That is, whether referrals for low-value testing are driven by a strong desire to diagnose a tricky condition, self-referral and profiteering, or "defensive medicine", there appears to be an across-the-board reduction in the number of such referrals when you change how you compensate doctors for the tests and the amount that patients must contribute in order to obtain the low-value test. Rates of malpractice litigation, damages caps and the like don't matter.

As long as any malpractice lawsuits are allowed, you're going to see doctors express that they fear frivolous lawsuits. History tells us that, short of a grant of absolute immunity, changing the tort system won't affect how doctors practice medicine. (The prior, ugly history of when doctors were all-but-immune from malpractice litigation should not be forgotten.) But, to the extent that defensive medicine even exists, if you can eliminate most or all "defensive medicine" by adjusting financial incentives, it's a peripheral issue - something that can be successfully addressed through indirect, economic reforms. Given that despite years of debate, there's still no consistent definition for or objective measure of what constitutes "defensive medicine", and "tort reform" has had no impact on its supposed practice, focusing on economics seems like the way to go.

1 comment:

  1. Wait, insurance companies are refusing to let doctors order the tests they want and are getting in the way of patients getting the tests they want, because their bureaucrats have determined those tests to have insufficient value to the patient? Why aren't people screaming about "death panels"?