Calculating the 10 Year Risk for Fatal Cardiovascular Disease Based on the SCORE Project Data

 

Method of analysis: Weibull proportional hazard model

 

Risk for cardiovascular disease is based on whether the patient is from a low-risk or high-risk region of Europe. Non-coronary cardiovascular disease involves stroke, peripheral vascular disease and other conditions not involving the coronary arteries.

 

For both coronary heart disease and non-coronary cardiovascular disease, calculate survival for current age and for 10 years from now:

 

survival probability for current age =

= EXP((-1) * EXP(alpha coefficient) * (((age in years) -20)^(p coefficient)))

 

survival probability in 10 years =

= EXP((-1) * EXP(alpha coefficient) * (((age in years) -10)^(p coefficient)))

 

Coronary Heart Disease

Risk	Gender	alpha coefficient	p coefficient
low	male	-22.1	4.71
	female	-29.8	6.36
high	male	-21.0	4.62
	female	-28.7	6.23

 

Noncoronary Cardiovascular Disease

 

Risk	Gender	alpha coefficient	p coefficient
low	male	-26.7	5.64
	female	-31.0	6.62
high	male	-25.7	5.47
	female	-30.0	6.42

 

For both coronary heart disease and non-coronary cardiovascular disease, calculate the weighted sum for risk factors:

 

weighted sum =

= ((beta factor for cholesterol) * ((serum cholesterol in mmol/L) - 6)) + ((beta factor for systolic blood pressure) * ((systolic blood pressure in mm Hg) - 120)) + ((beta factor for current smoking) * (points for current smoking))

 

where:

• Points for current smoking: 0 if not currently smoking, 1 if currently smoking cigarettes

 

beta factor	coronary heart disease	noncoronary cardiovascular disease
cholesterol	0.24	0.02
systolic blood pressure	0.018	0.022
smoking	0.71	0.63

 

For both coronary heart disease and non-coronary cardiovascular disease, adjust the current and 10 year survival for the weight sum.

 

adjusted survival probability for current age =

= (survival probability for current age) ^ (EXP(weighted sum))

 

adjusted survival probability for 10 years from now =

= (survival probability for 10 years from now) ^ (EXP(weighted sum))

 

For both coronary heart disease and non-coronary heart disease, calculate the 10 year survival probability:

 

10 year survival probability =

= (adjusted survival probability for 10 years from now) / (adjusted survival probability for current age)

 

For both coronary heart disease and non-coronary heart disease, calculate the risk of death in 10 years:

 

risk for death within 10 years for type of disease =

= 1 - (10 year survival probability)

 

The final risk for death within 10 years is calculated:

 

risk of death within 10 years =

= (risk for death within 10 years from coronary heart disease) + (risk for death within 10 years from non-coronary cardiovascular disease)