ADA 2009: New Blood Test Bridges Time Gap Between Serum Glucose and Hemoglobin A1c

Martha Kerr

June 12, 2009

June 12, 2009 (UPDATED June 23, 2009) (New Orleans, Louisiana) — Researchers at the Joslin Diabetes Center in Boston, Massachusetts, report that 1,5-anhydroglucitol (1,5-AG; GlycoMark) measurement could add valuable information to the assessment of glucose levels in diabetics.

Serum glucose levels provide instantaneous assessment of glycemia and the hemoglobin A1c test provides the average glucose level of the previous 2 to 3 months. In contrast, 1,5-AG provides information on blood glucose excursions over a period of days to weeks, said Sanjeev Mehta, MD, MPH, a researcher and pediatric endocrinologist at the Joslin Diabetes Center and instructor of pediatrics at Harvard Medical School in Boston.

Dr. Mehta presented results of 1,5-AG assessment in youth and young adults with and without type 1 diabetes here at the American Diabetes Association (ADA) 69th Scientific Sessions.

Dr. Mehta and colleagues assessed the utility of 1,5-AG testing in 139 patients, aged 12 to 35 years, with type 1 diabetes and with a disease duration that ranged from 4 to 29 years, and in 166 healthy controls.

Patients with diabetes had significantly lower 1,5-AG levels than the control population. Gender differences were noted within both groups. Female patients with type 1 diabetes had lower 1,5-AG levels than male patients (3.4 ± 1.6 vs 4.5 ± 2.3 μg/mL respectively; P = .003). For control subjects, 1,5-AG levels were 23.3 ± 5.9 μg/mL for females and 25.4 ± 7.1 μg/mL for males (P = .03).

"The 1,5-AG test informs families about glycemic performance in a shorter period of time than A1c and may help inform decisions about the use of more aggressive measures to assess glycemic variability, such as continuous glucose monitoring." Dr. Mehta told Medscape Diabetes & Endocrinology.

Dr. Mehta's group categorized 1,5-AG levels in 3 groups of patients with diabetes, defined according to A1c values: below 8%, between 8% and 9%, and above 9%. They concluded that 1,5-AG levels might offer unique information regarding glycemic status in youth and young adults with type 1 diabetes achieving an A1c below 8%.

For younger patients with A1c levels below 8%, "the test may uniquely contribute to the evaluation of glycemia beyond that provided by A1c," he said. "The 1,5-AG level may indicate the presence of significant hyperglycemic excursions at A1c levels below 8%. The modest variation in 1,5-AG levels in patients with A1c above 9% suggests that chronic hyperglycemia may limit the utility of 1,5-AG in this group," the Joslin researcher said.

Lori Laffel, MD, MPH, chief of pediatric, adolescent and young adult diabetes and endocrinology at the Joslin Diabetes Center and associate professor of pediatrics at Harvard Medical School, told Medscape Diabetes & Endocrinology that, "1,5-AG is useful for patients with suboptimal glycemic control to assess short-term therapeutic or behavioral interventions. For patients in moderate control, it may provide young patients and families with positive reinforcement that therapy is working."

Richard Bergenstal, MD, president-elect of the ADA, concurred: "1,5-AG is driven more by diet than A1c, but less than serum glucose. As glucose becomes more dominant, 1,5-AG becomes less so."

"The size of the child and the duration of diabetes is not related to the A1c value, while 1,5-AG is highly inversely correlated," said Dr. Bergenstal, who is director of the International Diabetes Center in Minneapolis, Minnesota. "Added to serum glucose and A1c, 1,5-AG gives a unique picture of glycemic profile from hours to months . . . and may give a picture of kidney function."

Dr. Laffel concluded that "1,5-AG is useful for patients with suboptimal glycemic control to assess short-term therapeutic or behavioral interventions. For patients in moderate control, it also provides young patients and families with positive reinforcement that therapy is working."

The study was sponsored by GlycoMark. Dr. Mehta and Dr. Laffel have disclosed no relevant financial relationships. Dr. Bergenstal reported financial relationships with Amylin Pharmaceuticals, Eli Lilly & Co, Intuity, Abbott Diabetes Care, Lifescan (a Johnson & Johnson Company), MannKind Corp, Medtronic MiniMed, Novartis Pharmaceuticals, and Novo Nordisk.

American Diabetes Association (ADA) 69th Scientific Sessions: Poster abstract 1802-P. Presented June 8, 2009.

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