Aims To assess any differences between coronary heart disease (CHD) risks c
alculated by the Framingham equation and those calculated by the PROCAM equ
ation in men with and without diabetes mellitus, and whether any such diffe
rences are associated with the hypertriglyceridaemia of diabetes mellitus.
Methods Clinical and biochemical data collected from 1774 men seen in eithe
r general practice, a hospital diabetes or lipid clinic. CHD risks were cal
culated by both the Framingham and PROCAM functions and comparisons made be
tween those patients with and those without diabetes.
Results Of the 1774 men only 996 fulfilled the criteria for assessment by t
he PROCAM equation and thus further analysis. Patients with diabetes mellit
us had significantly higher serum triglyceride levels than those without (1
.9 mmol/l vs. 1.7 mmol/l). Median annual CHD risks calculated by the Framin
gham function were 1.7% in the patients with and 1.32% in the patients with
out diabetes mellitus, whereas those calculated by the PROCAM function were
0.77% and 0.6%, respectively. Bland-Altman difference plots showed that in
both groups of patients the PROCAM equation systematically underestimated
risk in comparison with the Framingham equation at low levels of risk but o
verestimated at higher levels of risk. The shape of the plots in each group
of patients was, however, similar.
Conclusion There were no systematic differences between CHD risks calculate
d by the two different equations in patients with diabetes compared with th
ose without, despite the higher serum triglyceride levels associated with d
iabetes. Restrictions in the use of the PROCAM function meant that only 56%
of the original cohort could be assessed in this way. Thus the Framingham
equation remains the most suitable method of CHD risk prediction for UK pat
ients with and without diabetes mellitus.