Post-challenge hyperglycaemia relates more strongly than fasting hyperglycaemia with carotid intima-media thickness: the RIAD Study

Aims Only scarce information exists on the distribution and atherosclerosis risk in different types of hyperglycaemia at diabetes detection. This study aimed to analyse the occurrence of isolated fasting (IFH), isolated post challenge (IPH) and combined hyperglycaemia (FH/PH) among subjects detected to have diabetes and the association of these types of hyperglycaemia with cardiovascular risk factors and carotid intima-media thickness (IMT). Methods A total of 785 middle-aged subjects of the Risk Factors in Impaired Glucose Tolerance (IGT) for Atherosclerosis and Diabetes (RIAD) study underwent a 75-g oral glucose tolerance test and examination of various atherosclerosis risk factors. IMT was measured by B-mode ultrasound. Results One hundred and nineteen (15.2%) asymptomatic diabetic subjects were detected: of these, 35.3% with IFH, 26% with IPH and 38.7% with FH/PH. The level of risk factors was higher in diabetic vs. non-diabetic subjects. HbA(1c) and cardiovascular risk factors were in the same range for IFH and IPH except for active plasminogen activator inhibitor (PAI)-1 which was significantly higher in IFH. A higher risk burden was found in the FH/PH group vs. both IFH and IPH. IMT was as follows: non-diabetic subjects 0.85 +/- 0.18 mm, IFH 0.91 +/- 0.20 mm, IPH 0.94 +/- 0.18 mm, FH/PH 0.98 +/- 0.17 mm (P < 0.05 vs. non-diabetes). 2 h post-challenge glucose (2hPG) correlated more closely (r = 0.23, P < 0.001) to IMT than fasting plasma glucose (FPG) (r = 0.14, P = 0.004). The importance of 2hPG was confirmed by the direct comparison of FPG and 2hPG in a three dimensional analysis. A significant increase of IMT was only observed in the subgroups with abnormal post-challenge hyperglycaemia for both combinations with normal FPG and IFG. FPG category did not significantly add to IMT in either group of post-challenge hyperglycaemia. Regression analysis in the whole sample revealed 2hPG but not FPG as a significant determinant of IMT. Further significant risk factors were age, male sex, total cholesterol, HDL-cholesterol and hypertension. Conclusions The RIAD study population at high risk for Type 2 diabetes mellitus, post-challenge hyperglycaemia was found to relate more strongly than fasting hyperglycaemia with carotid IMT.