Wednesday, January 20, 2010
More on practice variation: Hypertension
Following up on yesterday's data about practice variation with regard to endoscopies, here is another presentation from Blue Cross Blue Shield of MA regarding treatment of hypertension.
Here's the technical explanation, provided by a colleague at BCBS:
Two medicines -- ACE-inhibitors and Arbs (Angiotensin receptor blockers) are clinically interchangeable.* ACE-inhibitors cost substantially less than Arbs. The very high rate of Arb use (23% on average) is a good example of unexplained practice variation.
We see a wide spread in cost of treatment between the lowest quartile and the top quartile. A significant component of that, 30%, is accountable to the drug cost. And over 40% of the doctors have a use of Arbs that is above the network average.
And now look below at one particular 12-doctor primary care group, where the use of Arbs ranges from 13% to 55% and where three-quarters of the group are above the network average.
I recognize that the data don't tell us everything, but they suggest areas for inquiry. Let's beware, though, of demanding more and more analysis and data before reaching the conclusion that there is no underlying problem of practice variation.
In a comment below, I quote Paul Batalden from a seminar I attended months ago:
Measurement is a reductive act. We measure an aspect of a phenomenon. We often start with one or a few measures. A "natural" reaction is to want a more representative picture of the phenomenon -- hence a "breeder reactor" for measurement.
His point, I think, is that you have to start somewhere and see what you can learn, but if you think you are ever going to satisfy all of the data needs that definitively prove something, you will never reach that point of certainty.
*There is one minor caveat: A small percent of the population has a sensitivity to ACE-inhibitors, such that they develop an annoying (though benign) cough. Most docs suggest that could be about 10 to no-more-than 15% of a patient population. So Arb would need to be used on that small group.
Posted by Paul Levy at 1/20/2010 05:24:00 AM