Half of people 50 years and younger with low 10-year risk of CVD have high lifetime risk

Jan 15 2009

About half of people 50 years and younger who have a low 10-year or short-term cardiovascular disease (CVD) risk may have a high lifetime risk, researchers report in Circulation: Journal of the American Heart Association.

Typically, physicians determine patients' risk based on the Framingham Risk Score (FRS), a measure that helps to predict CVD risk during the next 10 years.

"However, our study's findings suggest that using only the traditional scoring method might be a missed opportunity for prevention," said Jarett D. Berry, M.D., M.S, lead author of the study.

"One of the limitations of using the traditional method is that most adults who are 50 years and younger have a low 10-year risk. This reflects the importance of age in determining cardiovascular disease risk," said Berry, assistant professor of medicine in the Division of Cardiology at the University of Texas Southwestern Medical Center in Dallas. "We wanted to determine if the addition of a lifetime risk estimate to the 10-year risk estimate would give us a better understanding of which individuals in this age group might have a higher prevalence and progression of undetected atherosclerosis."

Researchers found long-term risk estimates provide novel information about risk prediction that's not obtained through modifications of the 10-year risk window. For example, adjusting the threshold of "low risk" to less than 5 percent will do little to improve stratification of risk across the remaining lifespan.

Because of the intuitive nature and distinct features of lifetime risk estimates, researchers sought to combine the 10-year and the lifetime risk window into a single, clinically relevant method of risk stratification.

Researchers analyzed 10-year and lifetime risk scores for nearly 4,000 people age 50 and younger who had not yet had a heart attack. They found that 91 percent of those 50 and younger were at low risk for CVD, according to the Framingham Risk Score. Among that 91 percent, about half of them had a high lifetime predicted risk.

"The thickness of the carotid artery and amount of calcium in the coronary artery was significantly greater among those who had low short-term, but high lifetime risk, compared to those with low short-term and low lifetime predicted risk. So, by using many of the same risk factors of the Framingham Risk Score in a lifetime risk model, we reclassified nearly 50 percent of the people who were 'low-risk' by Framingham."

Using a long-term risk measurement for adults age 50 and younger could be a useful addition to the traditional 10-year risk score, Berry said.

"We feel that this study emphasizes the role of lifetime risk estimates as a useful adjunct to the 10-year risk estimate. At a minimum, we believe that lifetime risk estimates could be used to communicate risk more effectively to adults younger than 50 with elevated risk factors," he said.

Nearly 2,400 Americans die of CVD each day, an average of one death every 37 seconds, according to the American Heart Association. Cardiovascular disease claims about as many lives each year as cancer, chronic lower respiratory diseases, accidents and diabetes mellitus combined.

The National Heart, Lung, and Blood Institute funded portions of the study.

Co-authors are: Kiang Liu, Ph.D.; Aaron R. Folsom, M.D.; Cora E. Lewis, M.D., M.S.P.H.; J. Jeffrey Carr, M.D., M.S.; Joseph Polak, M.D., M.P.H.; Steven Shea, M.D., M.S.; Stephen Sidney, M.D., M.P.H.; Daniel H O'Leary, M.D.; Cheeling Chan, M.S.; and Donald M. Lloyd-Jones, M.D., Sc.M. Individual author disclosures are available on the manuscript.

Statements and conclusions of study authors that are published in American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect the association's policy or position. The association makes no representation or guarantee as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at www.americanheart.org/corporatefunding.