How About a Worldwide Effort to Collaborate on Developing Guidelines?
November 19, 2013
The 2013 AHA/ACC cardiovascular guidelines have been a topic of passionate debate and controversy all over the convention hall here in Dallas at AHA ‘13. From the plenary sessions, to poster halls, to Starbucks, to the media hall, everyone has something to say about the new guidelines. And they haven’t even been presented yet!
Many agree on the basic messages in the guidelines. These guidelines succeed in prioritizing statin therapy, which is supported by robust literature. Another positive of the new guidelines is that they take us beyond heart disease prevention to atherosclerotic cardiovascular disease prevention, adding stroke as an endpoint to the risk calculator. The guideline developers should also be commended for paying particular attention to underrepresented populations in constructing the risk calculators.
However, areas of concern are coming up again and again at the AHA. At the forefront is the concern about calibration of the risk calculator – so called “calculator-gate.”.Is it overestimating or is it doing what it is supposed to do? Paul Ridker and Nancy Cook have reported that the calculator is overestimating risk approximately2-fold in their evaluation of three different studies. The potential reasons could be related to the fact that the populations used in the new guideline had different populations from a different era with different environmental exposures, medication usage, and distributions of endpoints. In response, the AHA/ACC stood by the new calculator.
As the dust settles, many of us are wondering whether a recalibration of the calculator is being considered. I also can’t help but think: A risk estimate is just that – an estimate. In reality, there is a confidence interval around that estimate. Should we report the uncertainty with the estimate (report a range) to be more explicit about the roughness of the calculation?
Moreover, is a percentage risk over 10 years the most easily understandable value to use in clinic? Should we give an estimated range of “heart age” or “vascular age”? Perhaps comparing this with chronologic age that is, telling a patient, “your estimated vascular age is 10-15 years older than your actual age, could be more easily understood. This is especially the case since the new percentage 10-year risk isn’t on the same scale as the old percentage 10-year risk. The outcomes are different now. However, has anyone else noticed that this is being confused in the discussions surrounding this controversy?
A second major area of controversy is the fact that the new guidelines drop specific lipid targets. I’ve heard it repeatedly said at these sessions that this flies in the face of decades of science, prior US guidelines, and guidelines around the world. Yet these guidelines, which are focused on RCTs, are being touted as “evidence based.”.When we talk about “evidence based,”are we all talking about the same thing? The founders of evidence-based medicine defined it as “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.” What’s your definition of “evidence based?”
In moving forward, should we consider the totality of medical knowledge? Isn’t this done by other guideline developers in the US (e.g., ATP III, NLA) and around the globe, such as those guidelines in Europe, Canada, and Brazil. Why not aim to build upon and enhance these existing guidelines? Thinking even bigger, what about a worldwide collaboration to develop international consensus guidelines on cardiovascular disease? If our goals are to translate all medical knowledge, standardize and simplify recommendations, and optimally disseminate and implement, couldn’t we do this better as a worldwide team than on our own? It is my hope that following all of the passion and debate here at AHA ’13, everyone will stop and take a deep breath, and work together towards better treatment with the most reliable and relevant information to best treat our patients.