Formula Puts Doctor, Patient Glucose Readings on Same Page
Math converts two systems into better measurement, study says
SATURDAY, June 7, 2008 (HealthDay News) -- Researchers have found a mathematical relationship between two common blood glucose measurements that can help diabetics better monitor their condition.
An international study, published online in the August issue of Diabetes Care, describes the ties discovered between the three-month average glucose reading and levels of the A1C test and converting it to estimated average glucose (eAG). Most home-monitoring systems used by diabetics measure eAG in one type of unit, while A1C, which doctors have used for more than 25 years as the major measure of glucose control, is in different units.
It is extremely helpful for health-care professionals and patients to be using the same language to discuss glucose goals, Dr. Robert J. Heine, a professor of diabetology in the Department of Endocrinology at the VU University Medical Center in Amsterdam, the Netherlands, said in a prepared statement. Since patients sometimes find it difficult to understand the concept of glycated hemoglobin, it will be much easier to have all test results, both those from the lab and those the patient performs, in the same units.
The study, which examined 507 volunteers of various races and ethnicities with and without either type 1 or type 2 diabetes, confirms previous smaller studies.
Heine said the discovery will prove to be a valuable education tool. When health-care professionals set goals based on eAG units, then patients will know how close they are to reaching their goals every day when they test at home with self-monitoring, he said.
Most diabetics regularly use simple monitors that require pricking their fingers to obtain blood so they can check their blood glucose levels at home. The tests give blood glucose information only at that moment of the test.
A1C, by contrast, measures glucose control from the prior two to three months by reporting how much glucose has attached to a portion of the hemoglobin molecule in the blood. The American Diabetes Association recommends a goal of less than 7 percent for this test, which is also known as glycated hemoglobin testing.
"We developed an equation that can be interpreted accurately as an estimated average glucose level by comparing the measurement of A1C with the average glucose levels," study co-author Dr. Edward S. Horton, a professor of medicine at Harvard Medical School, said in a prepared statement. He was expected to present the study Tuesday at the American Diabetes Association's annual meeting, in San Francisco.
Horton cautioned that there are some limits to the study that will require further investigation. Some ethnic-racial groups, notably those of African and Asian descent, were under-represented; children and pregnant women were not studied, and patients with unstable glucose level or possible red blood cell disorders were also not included.
Educating diabetics and doctors about the relationship and how to take advantage of it, though, will soon begin by the American Diabetes Association (ADA), European Association for the Study of Diabetes, and International Diabetes Federation. The ADA Web site, www.diabetes.org, is already letting doctors purchase an inexpensive hand-held calculator that will quickly convert A1C values to eAG.
The American Diabetes Association has more about diabetes.