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Ask physicians if our messed up malpractice system causes them to practice “defensive medicine,” and most will probably say yes—hard not to be paranoid with so many lawsuits affecting so many physicians. Some experts even contend that major reforms of our malpractice system could go a long way towards controlling spiraling healthcare costs. On the other hand, if you ask physicians whether they ever order unnecessary tests for their patients, I expect most would say “no;” after all, that would be unprofessional.
In other words, it’s hard to get a handle on the true costs of defensive medicine.
But recently, a group of researchers led by Emily Carrier came up with a clever way of getting closer to such an estimate. They connected two pieces of previously unconnected data: physicians’ survey responses from 2008 in which they expressed how concerned they were about malpractice, and the same physicians’ test ordering behavior over the same period of time. That latter bit of data comes from Medicare, which gives researchers access to what is called “claims data”—records of the bills Medicare receives from physicians and hospitals.
In other words, the researchers were able to look at how paranoid physicians were about malpractice, and how many X-rays and CT scans they ordered for their patients.
For instance, physicians face a difficult judgment call when they see patients with low back pain. Most of these patients do not need X-rays or CT scans, but every once in a while that kind of a test will uncover an important problem that needs to be addressed quickly. Perhaps just as importantly, many patients want to receive such tests, if for nothing else than to receive reassurance about their problems. Does fear of malpractice cause physicians to order more tests in these kinds of patients?
Carrier’s study does not answer this question, because it only tests for association, not causation. But it does show quite an association. Among the physicians least worried about malpractice, less than 18% ordered conventional X-rays for such patients, a number that rose to almost 30% for those most worried about malpractice. Advanced imaging also was associated with malpractice fears, with 4% of those physicians unworried about malpractice ordering CT scans or MRIs versus 6% of those with significant worries.
A similar pattern showed up for evaluation of patients with headaches, another common complaint that rarely benefits from advanced imaging tests, but which can occasionally signal a serious illness that, if undetected, could lead to a lawsuit. Among those physicians not so worried about malpractice, around 6% ordered CT scans or MRIs for such patients, versus almost 12% of those with greater concerns about malpractice.
Time for a quick reminder on the importance of disentangling association and causation. Nothing about this study proves that malpractice fears caused these physicians to order more tests. It is possible, for example, that the same kind of physicians who worry about malpractice also worry about serious but rare illnesses. Take away their malpractice fears, and these physicians might still be just as worried about rare illnesses, and still order more X-rays and CT scans than their colleagues.
In addition, the same study showed no association between malpractice fears and the kind of tests physicians ordered for patients with chest pain. Even more importantly, the authors could find no association between test ordering behavior and the actual risk of malpractice lawsuits in different parts of the country.
The bottom line, then, is that we don’t have a real bottom line here. This was a clever study, which found a novel way to look at this important topic. But we are not much closer to understanding the true costs—financially and clinically—of defensive medical practice. We ought to reform the malpractice system in this country, for a whole host of reasons. But we should not necessarily expect such reforms to dramatically reduce the cost of medical care.
**Previously posted on Forbes**
