Predictive value of coronary calcifications for future cardiac events in asymptomatic patients with diabetes mellitus: A prospective study in 716 patients over 8 years

Background: To establish an efficient prophylaxis of coronary
artery disease reliable risk stratification is crucial, especially
in the high risk population of patients suffering from diabetes
mellitus. This prospective study determined the predictive value of
coronary calcifications for future cardiovascular events in
asymptomatic patients with diabetes mellitus. Methods: We included
716 patients suffering from diabetes mellitus (430 men, 286 women,
age 55.2 +/- 15.2 years) in this study. On study entry all patients
were asymptomatic and had no history of coronary artery disease. In
addition, all patients showed no signs of coronary artery disease
in ECG, stress ECG or echocardiography. Coronary calcifications
were determined with the Imatron C 150 XP electron beam computed
tomograph. For quantification of coronary calcifications we
calculated the Agatston score. After a mean observation period of
8.1 +/- 1.1 years patients were contacted and the event rate of
cardiac death (CD) and myocardial infarction (MI) was determined.
Results: During the observation period 40 patients suffered from
MI, 36 patients died from acute CD. The initial Agatston score in
patients that suffered from MI or died from CD (475 +/- 208) was
significantly higher compared to those without cardiac events (236
+/- 199, p < 0.01). An Agatston score above 400 was associated
with a significantly higher annualised event rate for
cardiovascular events (5.6% versus 0.7%, p < 0.01). No cardiac
events were observed in patients with exclusion of coronary
calcifications. Compared to the Framingham risk score and the UKPDS
score the Agatston score showed a significantly higher diagnostic
accuracy in the prediction of MI with an area under the ROC curve
of 0.77 versus 0.68, and 0.71, respectively, p < 0.01.
Conclusion: By determination of coronary calcifications patients at
risk for future MI and CD could be identified within an
asymptomatic high risk group of patients suffering from diabetes
mellitus. On the other hand future events could be excluded in
patients without coronary calcifications.