New guidelines on heart health that sparked fierce debate among US cardiologists last fall could lead 12.8 million more Americans to take cholesterol-lowering statin drugs, US researchers said.

The new estimate would mean 56 million people, or nearly half of the US population between the ages of 40 to 75, could be eligible for taking a statin to prevent heart disease. The findings were published on Wednesday in the New England Journal of Medicine's online edition.

Most of those would be people over age 60, according to the new analysis, which is the first to quantify the impact of the guidelines issued in November by the American Heart Association and the American College of Cardiology.

The recommendations represent a major change in assessing a person's risk for heart disease. Instead of working to lower a patient's "bad" LDL cholesterol to specific numeric targets, they ask doctors to embrace a new online calculator that factors in characteristics such as smoking and obesity to predict an individual's risk of heart disease.

Patients with a 7.5 percent or greater chance of having heart disease within 10 years would be considered eligible for treatment with a statin, such as Pfizer's Lipitor, known generically as atorvastatin, or AstraZeneca's Crestor.

Critics last fall said the risk calculator overestimated the number of people in need of treatment, and many speculated it would add tens of millions of new statin users.

Dr Steven Nissen, a cardiologist at the Cleveland Clinic who in November argued for a delay in implementing the guidelines, said the new analysis reinforces some of his concerns.

"It shows there is a huge expansion of the number of people for whom statins are recommended," he said in a telephone interview.

The increase is still lower than some estimates. In a blog post on the American Board of Integrative Holistic Medicine website on Dec. 15, Dr Jorge Bordenave, a cardiologist in Coral Gables, Florida, estimated the number of new statin users to be 31 million.

"There were a lot of opinions various experts expressed. Some quoted really high numbers," said Michael Pencina, a biostatistician at Duke University's Clinical Research Institute, who led the study published on Wednesday.

NATIONAL HEALTH SURVEY

To arrive at a more precise number, Pencina's team used data from the National Health and Nutrition Examination Surveys (NHANES), a representative survey of the US population. They focused on 3,773 participants between 40-75 who had provided detailed medical information, including fasting cholesterol levels from blood tests.

They compared recommendations for statin use under the new guidelines and the prior guidelines and extrapolated that number to the US population of 115 million adults aged 40 to 75.

Based on the analysis, the new guidelines could result in 49 percent of adults in that age range being recommended for statin therapy, an increase of 12.8 million people who would be newly eligible for a statin recommendation, a 38 percent increase from the older guidelines.

The increase was especially pronounced among adults over 60, with 77 percent recommended for statin use versus 48 percent under the prior guidelines.

That compared with an increase of between 27 percent and 30 percent among U.S. adults between the ages of 40 and 60.

The biggest impact of the change is among older healthy men who are not on statins. Under the earlier guidelines, some 30 percent of men age 60 to 75 were recommended for statin use. That number jumps to 87.4 percent under the new guidelines.

For healthy women over 60, the number newly recommended for statin use jumps from 21.2 percent to 53.6 percent.

Of course, not all who are eligible for statin treatment based on the risk calculator would get a prescription, Pencina concedes.

Dr Neil Stone, a professor of preventive cardiology at Northwestern University's Feinberg School of Medicine who chaired the committee that issued the new guidelines, said that is precisely the point.

Stone said the risk estimator was intended to be used as a tool to inform doctors and patients about the potential need for treatment.

"The risk estimator doesn't determine the statin prescription. It determines the need for a risk discussion," he said.

Dr Paul Ridker and Dr Nancy Cook of Brigham and Women's Hospital sparked controversy last fall by saying the risk calculator was flawed. They said the new study suggests that most of the patients newly eligible for statins will be older adults who smoke or have high blood pressure, but not high cholesterol.

"As the new guidelines correctly suggest, before initiation of statin therapy in these patients, physicians should first have a conversation about diet and exercise, and if relevant, smoking cessation and blood pressure control," they said in a statement.

Although the American Heart Association has said the risk calculator had been vetted by many experts, Nissen said it was never published in a peer-reviewed journal.

"We are now for the first time really beginning to understand who this risk calculator will recommend for treatment," he said.

Until there is more clarity, Nissen believes doctors will stick with what they know. "People are voting with their feet. We're not using the guidelines," he said. - Reuters