The End of Evidence-Based Medicine?

stains-cover-webA recent debate about statins in the British medical press — Lancet vs. BMJ! Cage fight! — has me wondering about a bigger question: the limits to what physicians and others in the health industry call “evidence-based medicine.” Let’s shorten that to EBM, and see what the problem is.

EBM is usually defined as “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.” Hard to argue with that. Of course doctors should weigh what the current evidence says about a treatment before subjecting their patients to it. There may be questions about what is accepted as “evidence” and who defines what’s “best,” But that shouldn’t be too hard, either. Most physicians that I’ve talked to (and most people in general) would think that evidence means carefully conducted scientific studies, and best means most reproducible and consistent. As a science writer, I’m all in favor of basing things like medical treatment on scientific evidence. So yay EBM.

If there’s any place EBM should work, it’s in the arena of statins, the biggest-selling, most widely prescribed prescription medicines of our time. They are also the most studied, with hundreds of scientific papers assessing their risks and benefits.

So why are we still debating their proper use? It might come down to something that the admirable Ben Goldacre wrote a couple of years ago, “If there is any uncertainty at all about the risks and benefits of statins – and there is – then we have failed to competently implement the most basic principles of evidence based medicine.”  In other words, the cure for this problem is more and better EBM.

But I don’t think it’s quite that. At least not only that. I encourage interested readers to read both sides of the statin debate summarized in the first link, as well as the bits that it links to. You’ll soon find yourself immersed — as I have been for the past few months — in a morass of evidence, a range of opinions about what that evidence means, and what appears to me to be a wall circumscribing EBM, a hard limit on what we can expect from basing medical practice on science. More studies — more EBM — won’t solve the problem.

Because the problem is rooted in places that EBM can’t go. In human greed and fallability, in our proclivity to adopt hard positions and defend them, in our personal ideas of what’s good for our society, and the ways in which these ideas conflict with others. EBM is misused by those who might profit from a particular angle, and when the stakes are high enough, will rarely lead to a consensus accepted by all. The same factors are at play in even bigger questions, like climate change. No amount of “evidence” is going to convince “skeptics.”

I spent several months going over the evidence about statins, and published my own reading of the issue here. (Spoiler alert: They are good for some people, bad for others; ; cause a bunch of side effects that range from annoying to life-threatening; can save many lives in high-risk groups but are relatively useless in populations who are at low-to-moderate risk of heart disease. There are equally effective, less risky alternatives for many patients. Bottom line: Statins are way, way, way overprescribed.)

That’s my opinion. It conflicts with the opinion of others. And as much as I hate to say it, I have little faith that the answer to that conflict will come from EBM.