Clinical Usefulness of the Framingham Cardiovascular Risk Profile Beyond Its Statistical Performance: The Tehran Lipid and Glucose Study

Abstract

The utility of a risk function in clinical practice is an important concept that has received insufficient attention. The authors evaluated the clinical usefulness of the Framingham risk function (FRF) for cardiovascular disease in a Middle Eastern population (2,640 men and 3,584 women aged 30-74 years) free of cardiovascular disease at baseline in 1999. They calculated the net benefit fraction for treatment of subjects with an estimated 10-year risk of 10% and also 20%, where the net benefit fraction is a weighted sum of true-positive and false-positive rates divided by incidence, as estimated by Kaplan-Meier analysis. The authors drew a decision curve by plotting the net benefit fraction against a wide range of risk thresholds for treatment. The cumulative incidence of cardiovascular disease was 7.6% and 12.3% in women and men, respectively. The FRF had a C index of 0.832 in women and 0.785 in men with a reasonable calibration. On the basis of the net benefit fraction, about 50% of the incidence in men and women could be appropriately treated by using the 10% threshold; however, the FRF was not useful at the 20% threshold, especially in women. In both genders, usefulness of the FRF was as good as the function derived directly from Tehrani data with the same variables; however, it could be useful in low thresholds for treatment. cardiovascular diseases; decision support techniques; epidemiologic methods; forecasting; Kaplan-Meier estimate; proportional hazards models; risk