Relationship of glycated albumin to blood glucose and HbA_1c values and to retinopathy, nephropathy, and cardiovascular outcomes in the DCCT/EDIC study

The association of chronic glycemia, measured by HbA_1c, with long-term complications of type 1 diabetes has been well established in the Diabetes Control and Complications Trial (DCCT) and other studies. The role of intermediate-term and acute glycemia and of glucose variability on microvascular and cardiovascular disease (CVD) is less clear. In order to examine the interrelationships among longterm, intermediate-term, and acute measures of glucose and its daily variability, we compared HbA_1c, glycated albumin (GA), and seven-point glucose profile concentrations measured longitudinally in a case-cohort subpopulation of the DCCT. HbA_1c and GA were closely correlated with each other and with the mean blood glucose (MBG) calculated from the seven-point profile. The associations of glucose variability and postprandial concentrations with HbA_1c and GA were relatively weak and were further attenuated when MBG was included in multivariate models. In the case-cohort analyses, HbA_1c and GA had similar associations with retinopathy and nephropathy, which were strengthened when both measures were considered together. Only HbA_1c was significantly associated with CVD. The demonstrated interrelationships among different measures of glycemia will need to be considered in future analyses of their roles in the development of long-term complications of type 1 diabetes.