Category Archives: Medicine

More Deafening Silence

From a review of medical licensing:

By almost all accounts, the quality of services consumers get from non-physician clinicians is at least on par with what they would get from a physician performing the same services. Dozens of peer-reviewed studies compare outcomes in situations where patients are treated by a physician, a physician assistant, or an advanced practice nurse.  Outcomes appear similar [15] – an important factor, considering that non-physician clinicians can provide many services at a much lower cost. …

A review of more than 50 studies by the American Medical Association’s Council on Medical Education found that the peer reviewed studies "almost uniformly conclude that . . . a non-physician clinician. . . can provide an acceptable level of care."  The Council did note that some observers find serious flaws in the literature, including small samples, lack of control subjects, and failure to control for differences in the severity of illness treated by physicians and non-physician clinicians. Nevertheless, physician groups are unable to point to studies showing worse health outcomes with mid-level clinicians.

Again a deafening silence.  Dozens of studies over decades consistently find no patient health differences between expensive docs and cheaper clinicians, but there is zero momentum to let clinicians replace docs – policy trends go the other way.  The "establishment" complains about flaws in existing studies, but feels no need to do better studies.  What is the point of social science if even relatively clear important results are ignored? 

Don’t tell me this is just because the public hasn’t heard about these studies – the media  covers lots of med news they think the public wants to hear.  My local paper has a whole weekly health section.  Obviously the media doesn’t think the public wants to hear how they can drastically reduce med costs without sacrificing health.  Medicine is not about health. School is not about Learning.  FYI, here are some of those many studies: 

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Noble Lies?

A New Scientist book review:

In the face of life’s inconvenient facts – alcoholism, drug addiction, depression and craziness, to name a few – pseudoscientific medical concepts allow us to cast difficult moral problems as simple factual questions, readily soluble in the lab and in the hospital. Gary Greenberg’s The Noble Lie is an impressive and fascinating round-up of such pseudoscientific notions and the ways in which they have come to count as genuine illnesses.

For instance, Greenberg explains how alcoholism’s transition from vice to disease was a welcome one, especially following Prohibition. It was long viewed as an allergy, though the specific allergen persistently failed to appear. Even today, neither its disease-nature nor any possible cures have manifested themselves. Regardless, people are happy to accept the idea that addiction is a medical illness, perhaps, Greenberg suggests, because of our ambivalence towards the role of pleasure and our uncertainties about free will and self-determination. "With the disease model we have an answer," he writes, "one that has the imprimatur of science; addiction isn’t wrong, it’s sick."

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Deafening Silence

Dan Klein harps on a too-rarely-asked question:

Counterparts to the FDA function in other countries. The FDA could adopt a standing policy that drugs permitted in Europe, Canada, Japan, Australia, etc. automatically become permitted in the US. Why doesn’t the FDA adopt such a policy? Is it because a drug that is safe and effective in Australia, Canada, or France may not be safe and effective in the United States?

Alex Tabarrok, in the office next door, says he often harps on this and has never heard a reasonable counter-argument.  I’m especially fascinated by situations like this, where a devastating argument against a status quo policy is met by complete silence and disinterest.  Why don’t intellectuals feel any need to respond to such arguments?  How can we make such silences more audible to more people?

Kids often analogously complain  "But Billy’s parents let him do X."  And they should add, "What makes you think you know better than Billy’s parents?"  Are we similarly just overconfident in the judgment of "our" regulators? 

Alex also harps on another tough question:

What can we learn about the need for efficacy requirements from the pervasive experience of off-label medicine, which has no FDA efficacy certification? The thrust of Tabarrok’s argument is that off-label seems to work quite well and so why not drop efficacy requirements entirely?

Alex tells me the two best counter arguments are that off-label uses are often similar to on-label uses, and that drug firms have low incentives to run tests near the end of a drug’s patent lifetime.  But then why not approve only similar on-label uses and approve all uses of unpatentable drugs (that have passed safety tests)? 

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Beware High Standards

300,000 useless knee surgeries annually, costing $1.5B, continue in the US because a ’02 study finding them useless "was criticized as flawed."  Now a new study finds the same results but "also has weaknesses."  We sure wouldn’t want anyone to change beliefs or behavior because of a criticizable study – not when there are all those impossible-to-criticize studies out there. The news:

One of the most common surgical procedures performed in the United States — arthroscopy to treat arthritis in the knee — is useless. … [The] findings are being published in today’s issue of the New England Journal of Medicine. … The study marks the second time a major study has questioned the operations, which can cost about $5,000 and are done on hundreds of thousands of Americans each year. In 2002, a study found the operations were no better than a sham procedure for arthritis. A year later, based on that and other studies, Medicare stopped paying for the operations for severe arthritis of the knee, and the number of claims for the procedure plunged.

But the 2002 study was criticized as flawed: All the operations were done by one surgeon, and the subjects, who were all men, tended to be older than the typical patient. As a result, many surgeons continued to perform the procedures. Feagan says that as many as a third of the estimated 950,000 arthroscopic knee surgeries performed each year in the United States are probably still being done for arthritis, which affects about 27 million Americans.  …

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Top Docs No Healthier

My two years a RWJF Health Policy Scholar exposed me to enough data to make me a skeptic on the marginal aggregate health value of medicine.  But where data is silent I try to give medicine the benefit of the doubt, such as in assuming average values are higher than marginal values, and that top med school docs give more value than others.   So I am shocked to report that in a randomized trial of 72,000 hospital stays by 30,000 patients, patients of top med school docs were no healthier:

The school affiliated with Program A is the top school in the nation when ranked by the incoming students’ MCAT scores, and it is always near the top. In comparison, the lower-ranked program [B] that serves this VA hospital is near the median of medical schools. … [Added: other ways A beats B here.] Patients treated by the two teams have identical observable characteristics and have access to a single set of facilities and ancillary staff. …

Health outcomes are not related to the physician team assignment. … Program B is associated with … a 0.3 percentage-point reduction in 5-year mortality (or 0.6% of the mean).  … The confidence interval is [-0.0162, 0.0106]. …

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Randomised Controlled Trials of Parachutes

It is tempting to react to unscientific methods of medical practice by rejecting any treatment that isn’t supported by rigorous scientific evidence.  Here’s a parody of naive implementations of evidence-based medicine that demonstrates the pitfalls of doing so:
Smith GCS, Pell JP. (2003). Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. BMJ, 327(7429), 1459-1461.

From the paper:

Results We were unable to identify any randomised controlled trials of parachute intervention.

Conclusions As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.

There are some interesting comments on the paper here and here.

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Good Medicine in Merry Old England

Here’s the abstract of an article by Martin, Rice, & Smith in the current issue of the Journal of Health Economics (generally regarded as the top journal in the field):

Empirical evidence has hitherto been inconclusive about the strength of the link between health care spending and health outcomes. This paper uses programme budgeting data prepared by 295 English Primary Care Trusts to model the link for two specific programmes of care: cancer and circulatory diseases. A theoretical model is developed in which decision-makers must allocate a fixed budget across programmes of care so as to maximize social welfare, in the light of a health production function for each programme. This yields an expenditure equation and a health outcomes equation for each programme. These are estimated for the two programmes of care using instrumental variables methods. All the equations prove to be well specified. They suggest that the cost of a life year saved in cancer is about £13,100, and in circulation about £8000. These results challenge the widely held view that health care has little marginal impact on health. From a policy perspective, they can help set priorities by informing resource allocation across programmes of care. They can also help health technology agencies decide whether their cost-effectiveness thresholds for accepting new technologies are set at the right level.

One shouldn’t overstate the importance of this; it’s only one study and it only deals with two medical conditions.  And of course the study was done on English data, not U.S. data.  We all know that there is evidence that the marginal unit of U.S. medicine has little or no health benefit, so this would be a noteworthy result if the study were done on U.S. data.  I don’t know how noteworthy it is for English data.  Does anybody know if there is any RAND study type evidence about the effectiveness of the marginal unit of medicine in England or in other European countries?

When I was a kid, a cousin who lived in England came to visit us and showed me how to crack open those little plastic cubes containing the four one-use camera flashbulbs we had back then and set them off with a battery.  That totally rocked my world.  So as far as I’m concerned those guys are all geniuses.

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Doctor, There are Two Kinds of “No Evidence”

I have a relative who has cancer and has been taking a particular chemotherapy drug.  It has been very successful; all of the tests and scans have been coming back negative for some time.  Recently I went along to an appointment with a fancy consulting oncologist to get his opinion about how much longer to continue with the drug.  Going into the appointment, I had the idea (based on nothing but what seemed to me like common sense) that there was a tradeoff: more chemo means a higher chance that the cancer won’t reappear, but also means a higher chance of serious side effects, and that we were going there to get his opinion on whether in this case the pros outweighed the cons or vice-versa.  What he said instead was that there was "no evidence" that additional chemo, after there are no signs of disease, did *any* additional good at all, and that the treatments therefore should have been stopped a long time ago and should certainly stop now.  I asked him what was incorrect about the (seemingly) common sense notion that additional chemo might get rid of the last little bits of cancer that are too small to show up on scans, and he said, more or less, that it’s not my idea of common sense that matters, it’s the evidence, and there is no evidence that things work that way.  So then I asked him whether by "no evidence" he meant that there have been lots of studies directly on this point which came back with the result that more chemo doesn’t help, or whether he meant that there was no evidence because there were few or no relevant studies.  If the former was true, then it’d be pretty much game over: the case for discontinuing the chemo would be overwhelming.  But if the latter was true, then things would be much hazier: in the absence of conclusive evidence one way or the other, one would have to operate in the realm of interpreting imperfect evidence; one would have to make judgments based on anecdotal evidence, by theoretical knowledge of how the body works and how cancer works, or whatever.  And good people, maybe I’m being unfair and underestimating this guy, but I swear to you that this fancy oncologist in this very prestigious institution didn’t seem to understand the difference between these two types of "no evidence."  So while he had a very strong and very (generally) laudable instinct that one ought to base one’s medical opinions on evidence rather than instinct, he seemed to be unable to avoid what strikes me as a pretty fundamental mistake.*  I’d love to hear thoughts about this, particularly from doctors who either have something to say about whether this is a common mistake among doctors or who have something to say about the chemotherapy question itself.

*The most generous possible interpretation of what went on, but which would require me to attribute to him a thought process that he did not express at all, is that he understands the difference between the two types of "no evidence" but has come to believe that doctors’ interpretations of imperfect evidence will systematically lead them to over-treat and so has adopted a rule of "do nothing unless there is strong evidence that you should do something" as a second-best optimum.

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Ignore Prostate Cancer

A US task force says don’t bother with prostate cancer tests:

The blood test that millions of men undergo each year to check for prostate cancer leads to so much unnecessary anxiety, surgery and complications that doctors should stop testing elderly men, and it remains unclear whether the screening is worthwhile for younger men, a federal task force concluded yesterday. …  The 16-member U.S. Preventive Services Task Force … published the new guidelines today in the Annals of Internal Medicine. …

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Gary Taubes, “Good Calories, Bad Calories”

Gary Taubes, a correspondent for Science magazine, contributed to the Atkins Diet craze with his New York Times article several years ago, "What If It’s All Been a Big Fat Lie?." He then spent the past several years expanding on that article, and the result Good Calories, Bad Calories, a book of some 600 pages (nearly 70 of which are the bibliography).

Taubes has several overarching themes; he contends, for example, that eating refined carbohydrates is what makes you obese, and that refined carbohydrates contribute to many of what used to be called "diseases of civilization" (such as heart disease, which seems to have been less common in traditional cultures that ate less processed food, including Northern cultures that ate almost exclusively meat).  (These arguments are still controversial, although new evidence continues to support them.)

The most important theme, however, suffuses the entire book: bias in scientific inquiry

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