Friday, October 22, 2010

Comparative effectiveness 101

I have to say I do not understand the opposition to including costs into the comparative effectiveness research (CER) equation. Perhaps I simplify too much, but here is how I think about it.

Comparing two therapies is like using a microscope to focus at different levels of depth. Starting from the lowest magnification, we can ask "do they both work?" Of course in order to make this question answerable with data, we need to define what we mean by "work". Once we have defined that, the question becomes whether or not both comparators produce an effect in the same (desired) direction. If they do not, then the comparison can stop here, as the one with the positive direction of effect wins out. If they do both produce a desired effect, then we focus on the magnitude of that effect. There are several ways to do this, including comparison of 1). the effect size and variability of each to one another, 2). the proportion of patients who achieve a certain threshold of response (aka response rates), and 3). the adverse events frequency and severity. If these parameters are identical between the two, then the decision clearly hinges on the cost. Why is this so hard to accept? We would not want to pay more money for an identical car, so why would we pay more for a drug?

Of course, life is never quite this simple. Most of the time we will find small differences that are amplified by marketing messages as the reason to prefer a particular therapy. And this is all fine and good, and it is OK if a patient prefers one to the other because of some of these subtle differences. The question here becomes "how much are we willing to pay for a unit of this difference?" And unless the patient herself is willing to write the check, this is the pivotal issue facing our society today in the realm of the healthcare debate. So far our politicians have refused to do the real math, and are pandering to the opinion that we can pay for whatever we want in healthcare. This stance resonates with the public, terrified of the fictional death panels, and, more importantly, with the business of medicine, as this approach provides ample fuel for this engine of economic growth. But does it really improve our health, the primary goal of healthcare? I think not, just look at the state of our health and compare it to the rest of the world. And secondly, what is it doing to our national budget?

I will concede that I have simplified a complex issue. But not that much, believe it or not. With a modicum of math literacy people can easily wrap their brains around these concepts and make their own decisions, rather than being manipulated by disingenuous obfuscations of politicians concerned more with stuffing their coffers with corporate money than looking out for the well-being of the nation.