Friday, November 20, 2009

Evidence-based medicine.

To prepare you for what I think will be the next round of idiocy in the health-care debate, let's talk a bit about evidence-based medicine. It is pretty much what it sounds like, making medical decisions based on prognostic models built upon observed phenomena. In short, we believe this pill will work because when other people have taken it they experienced the desired outcome more frequently than can be explained by random chance.

Sounds logical enough, and you might think that this is the rational basis for all of medical practice. You'd be wrong. There's a major effort afoot in medical practice to move to evidence-based protocols, and it's been relatively quiet until we discovered that it doesn't make sense to do routine mammograms before age 50.

What does "doesn't make sense" mean? It means that the risks outweigh the benefits. In the case of mammograms the harm done from false positive results, and the burden of doing the procedure, harms more people than are helped by the early detection of tumors in the 40-50 year old age group. That's not an opinion, or a carefully-considered judgment, it is a fact. We can see this in the data. It doesn't require interpretation, it is as plain as the sunrise.

This cold, hard, fact is on a collision course with American medical consumerism, which operates on the notion that more is better, saving a life from preventable illness is worth any sacrifice, that we all deserve to get as much medicine as we might need--consequences and costs to others be damned.

In my opinion, much of the blame for this selfish and fearful mindset lays with the medical community itself, which because of "choice" and "market forces" has been placed in the position of having to appeal to patient preferences and shy from patient aversions, as if health-care was a consumer product. Insurance packages are advertised in terms of what and how much the consumer can get rather than how positive the outcomes will be. When hospitals and other organizations spend money telling people how comfortable they will make them rather than how healthy they will make them, you end up with the pickle we are in.

I am reminded of Dr. Grieve's magic pills. Dr. Grieve was a Texas country doctor who I had the good fortune of working with when I was a nursing student. I was caring for one of his patients in the hospital when I was puzzled about why the patient kept expressing a preference for getting discharged so she could go back to taking Dr. Grieve's pills. We had a full pharmacy in the hospital I was training in, I couldn't imagine why she would have to stop taking something that brought her such benefit while she was hospitalized, but she told me there was only one pharmacy in some little town that dispensed them, and she couldn't take them when she was in the hospital because she couldn't get out of bed. I told her I'd bring her whatever she needed and she looked at me impatiently and informed me that wasn't the problem. The problem was she couldn't go outside. I was baffled by this, but she seemed to think I was the idiot here, so I let it drop at that, being the nursing student and all.

I asked Dr. Grieve about it. He smiled broadly and fished a prescription bottle out of his bag, the label read "Take one daily after 30 minutes of vigorous walking." She couldn't take them in the hospital because she couldn't do the walking. He then told me, in all seriousness, that he never tried a new drug with a patient to treat a chronic illness until the chronic condition had failed to improve with these pills. If someone tried to take them without doing the walking, he just told them they wouldn't work without the walking. If they still wouldn't walk, he knew where he was with that patient and approached his plan differently.

No wonder I didn't see many of his patients during training. The pills, of course, were placebos.

That's evidence-based medicine. Try selling that on a billboard.

What I expect is going to happen is something analogous to the idiocy over death panels and the like. Those that are given to protect the interests of investors in health insurance companies will start to assert that this is yet another way that the government is going to ration health-care. That's not true, the new recommendations, if adopted (which they won't be), would save lives and reduce suffering. Fewer procedural-related deaths and injuries mean lower costs. That's not a theory, you can see it in the data, but it won't matter because people who are accustomed to the "more is better" model of consumerism in health-care are understandably going to see less as worse.

Sadly, the truth is that less is often better. Diagnostic screening procedures are not absolutely safe, nor are they absolutely accurate. Biopsies sometimes cause problems, and resources that are used in pursuit of a false positive (a determination that there is disease when there in fact is not) are resources wasted. With a lot of data, we can reliably predict when the risks outweigh the benefits. That's all these recommendations are about, but that's not how they will be seen by a public that feels cheated when some rich guy can get a full body scan and their insurance company won't pay for it. No one ever talks about the rich guy with the full body scan that ends up dying from a MRSA infection acquired after a useless biopsy.