estimations of the heart attack risk
(THE1LINK) -- Apparent problems
with an online calculator, released last week along with new cholesterol guidelines, prompted one
expert Monday to suggest implementation of the guidelines be postponed.
The risk calculator, meant
to assist doctors in evaluating patients' risk and treatment options for
cholesterol, appears to greatly overstate risk, according to a report Sunday in The New
York Times.
It could result in
millions of people being incorrectly identified as candidates for
cholesterol-lowering statin drugs, the report said.
The calculator,
released by the American Heart Association and the
American College of Cardiology, is a tool to evaluate a patient's
10-year risk of a heart attack. According to the new guidelines, if a person's
risk is above 7.5%, he or she should be put on a statin.
However, in a hastily
called telebriefing Monday morning, members of the committee who developed the
calculator and guidelines said that they knew about the risk of overestimation
before rolling out the assessment tool and that they welcome more information
to help refine it.
The tool, they said, is
only one part of evaluating patients' treatment options -- something that can
only be done with the help of a doctor.
No one should be
"mailed a prescription" based on the results of the assessment tool,
said Dr. Neil Stone, committee chairman. "There's got to be a
physician-patient discussion. ... We've put the physician back into crucial
decision-making."
However, "I can't
speak to whether the calculator is valid or not," Dr. Robert Eckel,
co-chair of the American Heart Association committee that wrote the new
guidelines and the association's past president, told THE1LINK. "That
needs to be determined.
"We trusted that
the calculator worked," he said. "We trusted that the calculator is
valid."
Concerns about the
calculator were first raised, according to the Times report, by Harvard Medical
School professors Paul Ridker and Nancy Cook.
In an analysis to be
published Tuesday in the medical journal The Lancet, a copy of which was
obtained by THE1LINK Ridker and Cook write they calculated 10-year risks using
the tool and compared the data to event rates using three large
previously-published studies in which participants' characteristics such as age
and smoking status were known.
The calculator
"systematically overestimated observed risks by 75 to 150 percent, roughly
doubling the actual observed risk," they wrote.
THE1LINK's Elizabeth
Cohen said when she used the calculator, putting in a 65-year-old man with
normal cholesterol levels and no risk factors -- normal blood pressure, no
diabetes and a nonsmoker -- the calculator said he needed statins.
Ridker and Cook had
pointed out the issue a year earlier when drafts were sent to them for review
as the guidelines were under development, the Times said.
Researchers apparently
did not receive the professors' responses, Dr. Donald Lloyd-Jones, chairman of
the committee that developed the equation, told the Times.
But Lloyd-Jones told
reporters Monday, "There's nothing wrong with these equations."
Committee members were
aware there could be "overestimation of risk in some populations," he
said.
On Saturday night,
members of the American Heart Association and the American College of
Cardiology held a meeting with Ridker. Officials said Monday they await more
information from the professor.
Lloyd-Jones said Monday
he looks forward to getting details of Ridker's data. But he said, "I
suspect he's looking at extremely healthy cohorts. We're looking at
representative cohorts."
The truth, he
predicted, is "somewhere in the middle."
"Our risk
assessment guideline doesn't tell you what to do. ... It just evaluates
risk," he said.
"The analysis by
Drs. Ridker and Cook is very concerning," said Dr. Steven Nissen, chief of
cardiovascular medicine at the Cleveland Clinic.
"Since the risk
calculator was not previously published, it now makes sense to halt
implementation of the guidelines so that independent physician scientists can
evaluate the accuracy of the risk calculator," Nissen told THE1LINK in an
e-mail.
"We have waited
many years for these guidelines. It seems prudent to wait a little longer to
make certain that the guidelines function as intended."
Attempts by THE1LINK to
contact Ridker and Cook on Monday were not immediately successful.
The new treatment
guidelines call for a focus on risk factors rather than just a patient's
cholesterol level.
At the time, Nissen
called them "an enormous shift in policy as it relates to who should be
treated for high levels of cholesterol."
The four questions to
ask to determine risk include: Do you have heart disease? Do you have Type 1 or
Type 2 diabetes? Do you have a bad cholesterol level of more than 190? And is
your 10-year risk of a heart attack greater than 7.5%?
According to the new
guidelines, if you can answer yes to any of those four questions, you should be
on a stain
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