Heart guidelines authors defend method of calculating risk
Dallas, Nov 18 (Reuters) - Top cardiologists who devised new U.S. guidelines for reducing risk of heart disease strenuously defended their risk-calculation tool from criticism that it greatly overestimates health risks and the need to be treated with statins.
Two Harvard professors, Dr. Paul Ridker and Dr. Nancy Cook, sparked the controversy by saying the guidelines overestimate risk of developing heart disease up to 150 percent for some populations, according to a report in Monday's New York Times. The report said their criticisms would appear Tuesday in the British medical journal The Lancet.
Their concerns spurred prominent cardiologist Steven Nissen of the Cleveland Clinic to call for a delay in putting the new guidelines into practice, the report said. Nissen could not immediately be reached by Reuters.
A half dozen cardiologists who helped formulate the guidelines over a four-year period criticized Ridker's own methodology at a hastily called news conference during the annual scientific sessions of the American Heart Association (AHA) in Dallas.
"We intend to move forward with the implementation of these guidelines," said Dr. Sidney Smith of the University of North Carolina, a past president of the AHA who was executive chairman of the guidelines committee.
"If we think there is something that will make them better, you can count on that we'll do it," Smith said.
The guidelines were created by panels of experts from the AHA and the American College of Cardiology and include a formula for calculating the risk of developing heart disease over 10 years.
The guidelines no longer focus mainly on reducing the level of "bad" LDL cholesterol to specific targets, but instead assess each patient's personal risk factors of developing heart disease.
People 40 to 75 years old found to have a 7.5 percent or higher risk of heart disease within the next 10 years, as assessed by factors plugged into the calculator such as being obese or having diabetes, are encouraged to be treated with cholesterol-lowering statin drugs, such as Pfizer Inc's Lipitor (atorvastatin).
"These guidelines have been vetted by multiple experts many, many times," AHA President Dr. Mariell Jessup said.
Authors of the new guidelines on Monday said Ridker based his conclusions of overstated risk on three large population studies that involved subjects who are far healthier than the general population.
The new guidelines were based on more representative populations and consider for the first time the risk of stroke and factor in African Americans, a group with a disproportionately high risk of heart attacks and stroke.
"We think we came up with a good risk assessment instrument," Smith said.
The guideline authors said Ridker notified them on Friday of his criticisms for the first time, and that they would appear in the Lancet.
Moreover, several members of the guidelines committee, in interviews, said Ridker reviewed the proposed guidelines in 2012 and did not cite any such concerns.
"We got his review and he did not say anything about these three population studies at that time," said David Goff, dean of the Colorado School of Public Health and co-chair of the risk-assessment guidelines.
Dr. Donald Lloyd-Jones, professor of preventive medicine at Northwestern University, said Ridker had not yet provided the guidelines committee with specific data that underscore his concerns.
"We used what we thought were the best available data," Lloyd-Jones said. "We'd all like to see Dr. Ridker's data instead of seeing this played out in the media."
Neither Ridker nor Cook could immediately be reached for a comment.
(Reporting by Ransdell Pierson; Editing by Maureen Bavdek)