New cholesterol guideline topic of heated discussions at AHA congress
At the AHA congress in Dallas, there was much debate about the recently published guidelines about cardiovascular prevention of the American College of Cardiology (ACC) en de American Heart Association (AHA).
There was much ado after a critical piece in the New York Times (NYT), in which it was stated that the new risk calculator as described in the new guidelines is incorrect and systematically overestimates CV risk. Based on this risk prediction equation, millions of people would be incorrectly considered candidates for statin treatment. The article is based on a comment that was published in the Lancet on Tuesday 19 November.
The NYT article describes how dr. Paul M. Ridker and Dr. Nancy Cook of Harvard Medical School addressed these issues already a year ago, when they received a manuscript of the guideline for revision. After the final guidelines became available last week on Tuesday, they concluded that the problems remained. It has been said that the guideline committee has never received the critical feedback of dr. Ridker and dr. Cook.
Saturday night the AHA and ACC held a closed meeting with dr. Ridker. On Monday a press meeting was held. Since then, the topic was the subject of heated debate at the AHA congress.
In the NYT article dr. Michael Blaha, director of clinical research at the Ciccarone Center for the Prevention of Heart Disease at Johns Hopkins University, that a problem might lie in that the calculator used reference values of over a decade ago. At that time, more people smoked and had strokes and myocardial infarction at a younger age. Important changes have been observed since then.
The NYT also reports that dr. Ridker and dr. Cook evaluated the calculator this week, by using data of three large studies (Women’s Health Study, Women’s Health Initiative, and Physician’s Health Study) with a follow-up of over ten years. They conclude that the calculator overestimates CV risk with 75 to 150%, depending on the population.
Dr. Smith, ex-president of th AHA and member of the guidelines committee, said on Sunday that the concerns raised by dr. Ridker and dr. Cook merit attention. He furthermore says in the NYT article that “a lot of people put a lot of thought into how can we identify people who can benefit from therapy. What we have come forward with represents the best efforts of people who have been working for five years.”
In the discussion on the guidelines it was pointed out that the three populations that dr. Ridker and dr. Cook examined, were unusually healthy, which may have caused the rates of myocardial infarction and stroke to be lower than expected.
In a response on its website, the AHA, together with the ACC, fiercely defends the risk prediction model and the cholesterol guideline. They underscore that the calculator and guideline have been developed based on the best available evidence. They are a component of the resources that a healthcare provider should use to assess whether a patient will benefit from statin treatment. Guidelines can never substitute sound clinical judgment.
The risk calculator provides an estimate of the 10-years risk of heart attach or stroke of an individual patient, but a higher score does not automatically mean that a patient should be on statins, says John Gordon Harold, M.D., president of the ACC, in the declaration on the AHA website. Harold adds that this risk assessment is a clear improvement over the previous model, since risk of both heart attack and stroke are estimated. Previous guidelines only focussed on the risk of heart attack. Moreover, these are the first guidelines that estimate risk for African Americans.
“We recognize a potential for overestimates, especially at the high end of risk,” said Dr. David Goff, the dean of the University of Colorado School of Public Health and the co-chairman of the guidelines’ risk assessment working group.
Those involved deny the need to delay implementation of the guidelines. One of the authors, dr. Donald Lloyd-Jones said that the risk scores will be adapted over time, so as to make them even better.
“We think we’ve done our due diligence,” said AHA president Mariell Jessup. “We have faith and trust in the people who developed the guidelines.”
PACE will continue to follow the discussions and update you on the developments.
Written by Judith Brouwer, PhD (editorial office PACE).
New York Times, 17 november 2013 ‘Risk Calculator for Cholesterol Appears Flawed‘ AHA newsroom, 18 november 2013 ‘Cholesterol guidelines are based on strong, evidence-based science‘ CardioBrief, 18 november 2013 ‘Controversy Erupts Over Accuracy Of Cardiovascular Risk Calculator For Guidelines‘
News • 13-11-2013
Literature • 20-11-2013 • Ridker PM, Cook NR