October 6th, 2014
Nissen Urges Prompt Revision of Cardiovascular Guidelines
Sparked by a new study that once again finds serious flaws in the cardiovascular risk calculator at the heart of the American College of Cardiology/American Heart Association cardiovascular guidelines, Steve Nissen states that “the ACC and AHA should promptly revise the guidelines to address the criticisms offered by independent authorities.” The CV risk calculator is a key component of the guidelines, since people are generally considered candidates for statins if they have a 10-year estimated risk of CV disease of 7.5% or higher according to the equations used by the calculator.
In a study published in JAMA Internal Medicine, Nancy Cook and Paul Ridker, analyzing data from the Women’s Health Study, offer fresh evidence that the cardiovascular risk calculator used in the ACC/AHA cholesterol guideline is flawed. They found that the predicted rate of cardiovascular disease using the guideline calculator was significantly higher than the actual observed rate in the trial. They considered and ruled out several “alternative explanations” for the discrepancy, including underascertainment of events and the increased use of statins and revascularization procedures in their population.
Noting that there have been at least seven studies now finding similar flaws in the CV risk calculator, they write that “recalibration of the pooled data sets might provide a solution to this problem.”
In his invited commentary, Nissen writes that “guidelines are effective only when they involve the participation and consent of the stakeholders whose behavior they intend to govern.” Because they were developed without “transparency and public involvement,” he writes, they “represent an important failure of guideline governance and oversight process. Rather than forging a consensus on cholesterol management, the guidelines have further polarized the debate on appropriate use of statin medications.”
Nissen calculates that overestimation of CV risk would lead to millions of additional U.S. patients receiving statins. “While statins are valuable drugs, particularly in secondary prevention, they do have downsides, and prudence requires not administering drugs to patients who will likely not benefit.”
In the future, Nissen proposes, risk calculators should be published and subject to external validation before being adopted. More generally, the guideline process “should be more open and transparent and include a public comment period.”
Elliott Antman, president of the American Heart Association, had the following response to the new publications:
“These comments are the same that we heard and addressed when we published the guidelines last year. Multiple publications since that time have validated the concepts and the utility of the risk assessment tool and cholesterol guidelines. In addition, we continue to receive positive feedback from healthcare providers who use the guidelines as a tool to drive discussions with their patients about appropriate care.”