The association of chronic glycemia, measured by HbA1c, 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 is less clear. In order to examine the inter-relationships among long-term, intermediate-term and acute measures of glucose and its daily variability, we compared HbA1c, glycated albumin (GA), and 7-point glucose profile concentrations measured longitudinally in a case-cohort subpopulation of the DCCT. HbA1c and GA were closely correlated with each other and with the mean blood glucose concentrations (MBG) calculated from the 7-point profile. The associations of glucose variability and post-prandial concentrations with HbA1c and GA were relatively weak and were further attenuated when MBG was included in multivariate models. In the case-cohort analyses, HbA1c and GA had similar associations with retinopathy and nephropathy, which were strengthened when both measures were considered together. Only HbA1c was significantly associated with cardiovascular disease. The demonstrated inter-relationships 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.
* A complete list of the members of the DCCT/EDIC Research Group is provided in the supplementary appendix published in New England Journal of Medicine, 2011; 365:2366-76.
- Received May 16, 2013.
- Accepted August 23, 2013.
- © 2013 by the American Diabetes Association.
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