An Italian chart for cardiovascular risk prediction. Its scientific basis

A risk chart for primary prediction of major coronary and cerebrovascular events based on Italian population data was created. Material from three Italian population studies was available: the Italian Rural Areas of the Seven Countries Study (no. 1712), the Gubbio Study (no. 3061) and the ECCIS Study (no. 4998) for a total of 9771 men and women aged 35 to 74 years and followed-up from 5 to 15 years, for a total of over 55,000 person/years. Sex, age, diabetes, cigarette smoking, systolic blood pressure and serum cholesterol were selected as risk factors, while the endpoint was established as the occurrence of the first major coronary or cerebrovascular event in 10 years. The accelerated failure time model was used as the predictive model. Two models were adopted, i.e., for relatively younger subjects (45-59 years) and for relatively older subjects (60-74 years). Both produced highly significant coefficients for each of the selected risk factors. The two models carried a satisfactory discriminating power, with 40% to more than 50% of all events located in the upper quintile of the estimated risk. Sex, age (6 classes), diabetes, cigarette smoking (4 classes), systolic blood pressure (4 classes) and serum cholesterol (5 classes) were considered for the creation of a risk map derived from multivariate models. A total of 1920 cells were filled with different colors corresponding to 6 classes of absolute risk. A similar set of cells was filled with another color scale for the estimate of the relative risk versus subjects of the same age and sex carrying Italian mean levels of risk factors. The chart is being distributed to the Italian medical profession as a practical tool to select high-risk individuals for the primary prevention of major cardiovascular diseases.