Reproducibility of individualized coronary heart disease risk calculations in patients with diabetes mellitus.
OBJECTIVE
To determine prospectively, the reproducibility of individualized coronary heart disease (CHD) risk estimations in a high-risk (diabetic) population.


METHODS
One hundred and three patients attending a hospital diabetes clinic who were in the primary prevention category for CHD had measurements of cholesterol, HDL-cholesterol and systolic blood pressure (SBP) performed in one of 13 general practices and then 2 weeks later in the hospital clinic. The data were combined with age, sex, smoking history and diabetic status data to produce a 10-year CHD risk estimate for each occasion using the Framingham algorithm.


RESULTS
The coefficients of variation for cholesterol, HDL and SBP were 6.0%, 9.4% and 7.0%, respectively. When classified by treatment thresholds of 15% and 30% 10-year CHD risk, 88% of patients were classified in the same category on both occasions. Kappa values for the 15% and 30% risk thresholds were 0.71 and 0.82. This indicates good interobserver agreement for the estimation of CHD risk. The use of a single BP rather than the mean of two, resulted in seven of 206 estimations of CHD risk performed in 103 patients crossing a risk threshold, with 6/7 being placed in a higher risk category.


CONCLUSIONS
Estimation of CHD risk on a single occasion is sufficient to make robust treatment decisions based on risk thresholds. Use of a single BP measurement rather than the mean of two overestimates the risk category in around 3% of cases.
Lambert
A P
AP
Department of Medicine, Weston General Hospital, Weston-super-Mare, UK. A.P.Lambert@bris.ac.uk
Hunt
M A
MA
Day
A P
AP
Bayly
G R
GR
Dayan
C M
CM
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D003327:Coronary Disease / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D003920:Diabetes Mellitus / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D004739:England / Q000453:epidemiology; D005194:Family Practice; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D018570:Risk Assessment; D012907:Smoking / Q000453:epidemiology; D013599:Systole
D008076:Cholesterol, HDL; D002784:Cholesterol