The first U.S. trial of the GlycoMark assay, demonstrated that 1,5-anhydroglucitol (1,5-AG) levels are a good indicator of glycemic control. This assay has Food and Drug Administration (FDA) clearance for intermediate term monitoring.
"1,5-Anhydroglucitol (1,5AG) is a major circulating polyol arising primarily from ingestion and excreted competitively with glucose," write Janet B. McGill, MD, from the Washington University School of Medicine in St. Louis, Missouri, and colleagues. "Japanese studies have demonstrated reduced concentrations of 1,5AG in serum in hyperglycemic patients in comparison with euglycemic subjects and a gradual normalization of 1,5AG values for patients responding to antihyperglycemic therapies."
Of 77 patients with suboptimal glycemic control at baseline, defined as HbA1c of at least 7%, 22 patients had type 1 diabetes and 55 had type 2 diabetes. Each patient received therapy targeted to reduce mean HbA1c by 1.0% over the monitoring period, consisting of combinations of diabetes education, nutritional counseling, and addition or dose adjustment of various insulins or oral antihyperglycemic medications. At baseline and at two, four, and eight weeks after treatment began, patients had 1,5AG, HbA1c, fructosamine, and random glucose measurements.
By week 2 of monitoring, 1,5AG, fructosamine, and glucose values progressed toward euglycemia (P < .05), with median changes of 93%, –7%, and –13%, respectively. However, HbA1c values did not change significantly until the fourth week of treatment. On an individual patient basis, 89.6% of patients had longitudinal changes in 1,5AG from baseline to week 8 reflecting changes in HbA1c. 1,5AG was also highly correlated with HbA1c (Spearman = –0.6459) and fructosamine (–0.6751; both P < .0001).
The authors note that these findings are consistent with those of Japanese studies in the past 20 years, and they recommend further studies to clarify the role of 1,5AG measurements in clinical diabetes management.
"We conclude that 1,5AG responds sensitively and rapidly to changes in glycemia and monitors glycemic control in accordance with established markers," the authors write. "The recent clearance granted by the FDA makes the GlycoMark assay available for intermediate-term monitoring, which, it is hoped, will allow patients to seek medical intervention in a timely manner, such as when initiating or altering therapy. This may empower patients to achieve and maintain better control of their disease."
We first reported on this valuable new test in June click here to read that introduction.
Diabetes Care. 2004;27:1859-1865
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