Common clinical practice versus new PRIM score in predicting coronary heart disease risk

Abstract

Objectives: To compare the new Patient Rule Induction Method (PRIM) Score and common clinical practice with the Framingham Point Score for classification of individuals with respect to coronary heart disease (CHD) risk.

Methods and results: PRIM Score and the Framingham Point Score were estimated for 11,444 participants from the Copenhagen City Heart Study. Gender specific cumulative incidences and 10 year absolute CHD risks were estimated for subsets defined by age, total cholesterol, high-density lipoprotein (HDL) cholesterol, blood pressure, diabetes and smoking categories. PRIM defined seven mutually exclusive subsets in women and men, with cumulative incidences of CHD from 0.01 to 0.22 in women, and from 0.03 to 0.26 in men. PRIM versus Framingham Point Score found 11% versus 4% of all women, and 31% versus 35% of all men to have 10 year CHD risks>20%. Among women ≥ 65 years with hypertension and/or with diabetes, 10 year CHD risk>20% was found for 100% with PRIM scoring but for only 18% with the Framingham Point Score.

Conclusion: Compared to the PRIM Score, common clinical practice with the Framingham Point Score underestimates CHD risk in women, especially in women≥65 years with hypertension and/or with diabetes.

Figure 1

Consecutively identified, mutually exclusive subsets with decreasing cumulative incidences of coronary heart disease using PRIM Score in women from the Copenhagen City Heart Study. The dataset contained 6,387 women, with an overall 10 year cumulative incidence of coronary heart disease of 0.07. The first subset was defined by two peeling (Age ≥65 and Hypertension Stage II–IV) and one pasting term (Diabetes) (pasting terms in italic). The process of producing a new subset based on the unassigned individuals from the previous partition continued until all individuals were assigned to a subset. The individuals that were not included in any of the statistically significant subsets were assigned to the remainder subset. N=number of individuals; CHD=cumulative incidence of coronary heart disease; HDL=high-density lipoprotein. Parentheses after CHD indicate the 95% confidence interval for the cumulative incidence. Age is in years and total cholesterol and HDL cholesterol are in mg/dL.

Figure 2

Consecutively identified, mutually exclusive subsets with decreasing cumulative incidences of coronary heart disease using the PRIM Score in men from the Copenhagen City Heart Study. The dataset contained 5,057 men, with an overall 10 year cumulative incidence of coronary heart disease of 0.14. The first subset was defined by one peeling (Age ≥65) term. The process of producing a new subset based on the unassigned individuals from the previous partition continued until all individuals were assigned to a subset. The individuals that were not included in any of the statistically significant subsets were assigned to the remainder population subset. N=number of individuals; CHD=cumulative incidence of coronary heart disease; HDL=high-density lipoprotein. Parentheses after CHD indicate the 95% confidence interval for the cumulative incidence. Age is in years and total cholesterol and HDL cholesterol are in mg/dL.

Figure 3

Ten year absolute coronary heart disease (CHD) risk in consecutively identified, mutually exclusive subsets identified using PRIM Score in women and men from the Copenhagen City Heart Study. Cumulative incidences (Figure 1 and 2) were transformed into 10 year CHD risks for the seven subsets in both women and men. Pasting terms are in italic. HDL=high-density lipoprotein. Age is in years and total cholesterol and HDL cholesterol are in mg/dL. CI= confidence interval; CHD=coronary heart disease.

Figure 4

Fraction of women and men with 10 year coronary heart disease risk >20% according to PRIM Score and common clinical practice with the Framingham Point Score. Comparison is shown for the different subsets identified with PRIM Score on the Copenhagen City Heart Study cohort with 11,444 individuals followed for 10 years (Figures 1 and 2). CHD=coronary heart disease.