Jan 23 2008
Physicians currently evaluate a patient's risk for heart disease, stroke and other cardiovascular diseases (CVD) individually, but a new assessment tool could gauge risk of overall 'or global' CVD and a range of cardiovascular diseases at one time, according to a study published in Circulation: Journal of the American Heart Association.
This new index is particularly well suited for use by office-based primary care physicians, who could estimate patients' overall CVD risk by using a simple, single scoring system, researchers said.
Applying the new system to 12 years of patient data, researchers found that the scoring index accurately assessed who would have a CVD event (such as stroke or heart attack). The index demonstrated accuracy for men and women for global CVD, and, with minor adjustments to the index, permitted reliable estimation of a person's risks for specific types of CVD.
“Individuals with a high overall CVD risk require more aggressive risk factor modification,” said Ralph B. D'Agostino, Sr., Ph.D., chair and professor of mathematics and statistics at Boston University and co-principal investigator of the Framingham Heart Study. “The goal of therapy for cholesterol disorders, diabetes and hypertension should be linked to the global CVD risk.”
D'Agostino and his colleagues analyzed data on 8,491 participants (average age 49) in the Framingham Heart Study, all of whom were free of CVD at the start of the study. The researchers used standard statistical methods to develop male- and female-specific scoring systems, or algorithms for estimating risk of developing a first CVD. These scoring systems incorporated age, levels of total cholesterol and high-density lipoprotein cholesterol, systolic blood pressure, treatment for high blood pressure, smoking and diabetes status. The researches then evaluated the algorithms' ability to estimate overall CVD risk and the scoring systems' accuracy for predicting the occurrence of individuals' CVD (coronary disease, stroke, peripheral artery disease or heart failure).
Over 12 years, 1,174 of the participants developed a first CVD diagnosis. Each of the risk factors incorporated into the global risk-assessment system correlated significantly with 10-year CVD risk. When study participants were separated into five groups (quintiles) according to risk score, the top quintile of risk scores identified 60 percent of women and 49 percent of men who had CVD.
The gender-specific global CVD risk-assessment algorithms were then adapted to predict the risk of the individual components of the global CVD risk. The process involved multiplying the risk predicted by the general risk scoring system by the proportion of the general first CVD diagnoses accounted for by an individual type of CVD. The results were compared with those produced by statistical models the researchers developed specifically for the individual components. The comparison showed that “the general CVD risk formulation provides as good discrimination of individual CVD outcomes as does the individual disease-specific” scoring systems.
The authors noted that several disease-specific systems have been developed to predict a person's risk of developing a specific type of CVD. Because risk factors for the different types of CVD are similar, a single risk-assessment tool that incorporates the common risk factors would help physicians predict a person's overall CVD risk as well as the risk for a given type of CVD.
“Our study was motivated by our presumption of a need to simplify risk prediction in office-based practices by replacing disease-specific algorithms with a single general global CVD prediction tool,” the authors said, adding that the validity in other populations should be evaluated in future studies.
http://www.americanheart.org/
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