OBJECTIVE -Postprandial hyperglycemia is often inadequately assessed in diabetes management. Serum 1,5-anhydroglucitol (1,5-AG) drops as serum glucose rises above the renal threshold for glucose and has been proposed as a marker for postprandial hyperglycemia. The objective of this study is to demonstrate the relationship between 1,5-AG and postprandial hyperglycemia, as assessed by the continuous glucose monitoring system (CGMS) in suboptimally controlled patients with diabetes.RESEARCH DESIGN AND METHODS -Patients with type 1 or type 2 diabetes and an HbA 1c (A1C) between 6.5 and 8% with stable glycemic control were recruited from two sites. A CGMS monitor was worn for two consecutive 72-h periods. Mean glucose, mean postmeal maximum glucose (MPMG), and area under the curve for glucose above 180 mg/dl (AUC-180), were compared with 1,5-AG, fructosamine (FA), and A1C at baseline, day 4, and day 7.RESULTS -1,5-AG varied considerably between patients (6.5 Ϯ 3.2 g/ml [means Ϯ SD]) despite similar A1C (7.3 Ϯ 0.5%). Mean 1,5-AG (r ϭ Ϫ0.45, P ϭ 0.006) correlated with AUC-180 more robustly than A1C (r ϭ 0.33, P ϭ 0.057) or FA (r ϭ 0.38, P ϭ 0.88). MPMG correlated more strongly with 1,5-AG (r ϭ Ϫ0.54, P ϭ 0.004) than with A1C (r ϭ 0.40, P ϭ 0.03) or FA (r ϭ 0.32, P ϭ 0.07).CONCLUSIONS -1,5-AG reflects glycemic excursions, often in the postprandial state, more robustly than A1C or FA. 1,5-AG may be useful as a complementary marker to A1C to assess glycemic control in moderately controlled patients with diabetes.
Diabetes Care 29:1214 -1219, 2006T he importance of tight glycemic control in preventing the complications of diabetes has been well documented (1-3). More recently, studies indicate that postprandial glucose may be an independent risk factor for the development of macrovascular complications (4 -6). Many patients who are otherwise well controlled by HbA 1c (A1C), the current standard indicator of overall glycemia, also have significant postprandial hyperglycemia (7). Currently, available markers for measuring glycemic control, including A1C and fructosamine (FA), only reflect average glucose, potentially missing important hyperglycemic excursions that may be balanced out by hypoglycemia. Therefore, an alternative marker that robustly reflects postprandial glucose excursions could be useful in the management of patients with diabetes.Plasma 1,5-anhydroglucitol (1,5-AG) is a naturally occurring dietary polyol that has been proposed as a marker for postprandial hyperglycemia. An automated assay (Glycomark) has recently been approved in the U.S. as a short-term marker for glycemic control (8), and a similar assay has been in use in Japan for over a decade (9). During normoglycemia, 1,5-AG is maintained at constant steadystate levels due to a large body pool compared with the amount of intake (10) and due to a lack of metabolism (10,11). Normally, in the kidneys, 1,5-AG is filtered and completely reabsorbed (12). However, with elevated serum glucose concentrations (generally Ͼ180 mol/l, the average renal threshold fo...