January 28, 2014
Common Blood Sugar Test Could Be Used For Early Diabetes Detection
A basic blood test used by diabetics to gauge their average blood glucose control over a two to three month period could also help diagnose the condition far earlier than previously believed, according to a new study appearing in the European Journal of General Practice.
According to researchers from Tel Aviv University's Sackler Faculty of Medicine and Clalit Health Services in Israel, an estimated 25.8 million Americans have Type 2 diabetes, and another 79 million have prediabetes, meaning they are at risk of developing the condition.
The American Diabetes Association (ADA) compares the A1C test to “a baseball player's season batting average” in that it reports a patient’s overall success over an extended period of time, focusing not on a single day but on the “big picture.”
Glucose is typically absorbed from the blood for use by various tissues in healthy men and women. However, the study authors explain that the cells of diabetes patients are resistant to insulin, a substance produced by the pancreas which helps regulate the body’s metabolism of fat and carbohydrates. Diabetics have higher blood sugar levels than healthy individuals, and those with prediabetes have glucose levels somewhere in the middle.
The A1C test is used to look for levels of glycated hemoglobin (A1C) in the blood. When blood sugar levels are high, more A1C is produced, allowing the substance to serve as a biomarker over an extended period of time. The test has primarily been used to monitor Type 2 diabetes, but in the past couple of years, the ADA and the World Health Organization (WHO) have added the test to their guidelines for the diagnosis of the disease.
The ADA said that having an A1C level of 6.5 percent or more is an indicator of the disease, while glycated hemoglobin levels between 5.7 percent and 6.4 percent are viewed as an indicator of prediabetes. The test is said to be easier to administer than most blood glucose tests, and does not require fasting or other eating habit changes.
“To evaluate the A1c test's ability to screen for diabetes in high-risk patients, the researchers analyzed the medical history of 10,201 patients who were given the test in central Israel between 2002 and 2005,” the university explained. “They found that overall, 22.5 percent of the patients developed diabetes within five to eight years.”
Patients who had A1C levels below the official diabetes diagnosis threshold (as low as 5.5 percent) were found to be significantly more likely to develop the disease than those who had glycated hemoglobin levels below 5.5 percent. Furthermore, each 0.5 percent increase in A1C levels up to 7.0 percent doubled the risk of developing diabetes. The researchers also found that obesity doubled a patient’s risk of becoming diabetic.
“We were actually able to quantify how risk increases with A1c levels,” said Dr. Lerner, who worked on the study along with professor Vinker Shlomo and Dr. Michal Shani of the Sackler Faculty of Medicine and Clalit Health Services. “This could allow doctors to make more informed decisions regarding diabetes prevention.”
“The study, one of the most comprehensive of its kind, provides compelling new evidence that the A1C test can accurately gauge risk at an earlier stage than is currently recognized,” the university added. “In combination with blood glucose tests and the identification of risk factors… the test could help doctors provide earlier treatment.”