Steven Nissen, MD: Risk Calculation is a Risky Business

November 13, 2018
Michaela Fleming

Steven Nissen, MD, discusses the updates to the cholesterol guidelines and how the risk calculator should not be considered an end-all be-all.

Earlier this week, the American Heart Association and the American College of Cardiology released updated guidelines for clinicians on the management of blood cholesterol. The updated guidelines, which were last updated in 2013, were presented at the American Heart Association Scientific Session in Chicago, Illinois.

The guidelines provided an update to the 2013 edition of the guidelines and provided new information regarding the risk calculator. The updated guidelines incorporate risk-enhancing factors” which include family history and ethnicity, and also take into consideration pre-existing health conditions.

In an exclusive interview, MD Magazine® sat down with Steven Nissen, MD, Chairman of the Department of Cardiovascular Medicine at the Cleveland Clinic to discuss the risk calculator component of the guidelines as well as his viewpoint on the inclusion of coronary calcium scanning.

[Part 1 of the interview is available here.]

Interview transcript: (modified slightly for readability)

MD Magazine®: A supplement to the guidelines indicates that the guidelines may include overestimates for some populations yet underestimate for others. Can you explain this?

Nissen: Well, first of all the whole business of developing a risk calculator is a risky business. The problem with risk calculators is that they’re based upon the available data at the time that the risk calculator is developed. But often the data is 5, 10, 15 years old. Well, it turns out with many of the public health measures, the use of better blood pressure lowering medications, and other factors these risk calculators are imperfect. And the pooled court equations, which were used in 2013, many of us thought were flawed right from the very beginning and they've gotten more and more flawed as time has gone on.

And so, you're seeing a kind of backing off on the idea that that risk calculator is the be-all and end-all, and more of a recognition that we need to think about these things. We need to look at these other factors like family history, and the presence of other risk factors that are not in those calculators, for example, inflammatory risk, high levels of c-reactive protein, something that I think is a very important factor in deciding who to treat. Well, they're now in these new guidelines and so there's a moving away from the idea that that risk calculator should be an absolute standard. It's really just a rough guideline about who should be treated and who shouldn't. We have to use common sense and good clinical judgment.

MD Magazine®: What are some areas of the guidelines that could be improved?

Nissen: Well, I have only one major disagreement with the guidelines. There is advocacy for coronary calcium scanning as a way to decide who to treat in those people that are intermediate, that are it's not clear [how] to treat. I do not favor this approach, this means using a test that involves giving patients radiation that can be fairly costly in order to decide whether to give a drug that can cost as little as $3 a month. I don't think it's cost-effective, I don't like the idea of exposing people to unneeded radiation and so I would argue that the advocacy for calcium scanning is an area that I like to see change.

Now interestingly enough the guideline writers in their press conference really soft-pedaled the idea of calcium scanning. They backed off quite a bit in the way they presented this to the media and I agree with that I think it's a test that's over-utilized and may, in fact, lead to unintended consequences. So, that's an area that I would like to see changed.

Perhaps one other area of controversy is the guidelines for the first time talk about the cost-effectiveness of medications like the PSCK9 inhibitors and the problem with addressing cost-effectiveness is it it's a moving target. The prices, for example, were recently dramatically reduced by about 60% for the PSCK9 inhibitors. Well, if you put a calculation into the guidelines about cost-effectiveness that's based upon pricing that's no longer the actual pricing, you're going to actually give erroneous advice. I would have preferred if they had not addressed price in the guidelines, I think guidelines ought to be about science then patients, providers, insurance companies, everybody else can talk about the cost issues.

The guidelines were published simultaneously in the American Heart Association journal, Circulation, and the Journal of the American College of Cardiology. The supplement, “Use of Risk Assessment Tools to Guide Decision-Making in the Primary Prevention of Atherosclerotic Cardiovascular Disease,” was also published in those journals.