Awareness Of Advanced Glycation Endproducts In Diabetes Care Is Growing
Advanced Glycation Endproducts In Diabetes
Results of an ongoing market research study of diabetes care providers found endocrinologists were universally aware of clinical tests that measure advanced glycation endproducts (AGEs), a biomarker known to be elevated in people with diabetes.
While awareness was also high among certified diabetes educators, less than one-quarter of primary care physicians surveyed were aware of AGE tests.
Commissioned by VeraLight, Inc., of Albuquerque, New Mexico, the independent study is being conducted by GfK Market Measures to gauge awareness of AGEs and tests that screen for diabetes and pre-diabetes. VeraLight is developing a non-invasive, one-minute diabetes screening system that uses light to detect skin AGEs regardless of skin color. Known as Scout DS(TM), the desktop system is being previewed at the annual meeting of the American Association of Diabetes Educators through August 4th at the America's Convention Center. Not yet approved for marketing in the United States, the investigational device is slated for U.S. market introduction in the second half of 2008.
"High awareness of AGEs among diabetes specialists is not surprising," said David Van Avermaete, CEO of VeraLight. "Numerous studies over the past 25 years have shown AGEs accumulate normally in skin, but are elevated in people with diabetes and are a predictor of the disease's serious complications. Broader education of the utility of non-invasive skin-AGEs in diabetes screening is needed, as we believe our studies will continue to confirm that Scout DS can detect diabetes and pre-diabetes earlier than conventional tests."
AGEs are formed when sugars chemically react directly with proteins or fats. They may be formed when cooking with high heat, or they can form inside the body through normal metabolism and aging. Analogous to a "diabetes odometer," AGEs are a sensitive metric for the cumulative damage the body has endured due to the effects of abnormally high blood sugar and oxidative stress.
In the course of medical research AGEs can be measured in serum and various tissues of the body. Until recently, the measurement of AGEs found in skin had no practical value as a commercial test because their measurement involved a punch biopsy of the skin (typically large enough to require a stitch), and a complicated assay that could only be performed by a few academic laboratories. AGEs have a robust optical signature that can be detected and measured via spectroscopic analysis. But prior to the development of proprietary Spectroscopic Advanced Glycation Endproduct (SAGE) detection technology by VeraLight, no one had determined how to normalize this signature for variations in skin color, blood content and structure. This prevented its practical use as an accurate, reproducible screening test.
Skin-AGE Detection Outperforms Conventional Diabetes Screening
Published in the May 2007 issue of Diabetes Care, a study of the Scout DS prototype involving 351 subjects showed it significantly outperformed both the fasting plasma glucose test (FPG) and the hemoglobin A1C test (A1C) by detecting 29% more patients with type 2 diabetes and impaired glucose tolerance (IGT) than FPG and 17% more cases than A1C. Further evaluation of a sub-cohort of the clinical data showed the Scout DS prototype was able to identify 78% more individuals with IGT than the FPG test and 47% more than the A1C test.
The FPG test misses up to 60% of the people it is trying to identify due to poor sensitivity, and the OGTT suffers from poor reproducibility with a Coefficient of Variation of 18%. These deficiencies can lead to false-negative or inconsistent results and add to the undiagnosed problem.
The Scout DS is currently undergoing a large-scale pivotal trial in the United States. A calibration trial of 1,850 subjects at risk for type 2 diabetes has completed data collection at eight U.S. sites. This phase of the trial is designed to assure its ability to predict abnormal glucose tolerance in a wide range of individuals. Interim results based on 853 subjects at four clinical trial sites (San Diego, Minneapolis, Chicago and Washington, D.C.), showed Scout DS had a sensitivity of 71% for detecting abnormal glucose tolerance. In contrast, the FPG test had a sensitivity of 56% and the A1C test had a sensitivity of 58%. All measurements were made at a 20% false positive rate.
Scout DS is undergoing further testing at 20 U.S. sites with 4,000 subjects at risk for type 2 diabetes. In all cases, the device is being compared to the OGTT as the reference method.
Scout DS Diabetes Screening System
Weighing about 10 pounds, Scout DS is a simple-to-use device that does not require the patient to fast or provide a blood sample. Using light directed onto a small area of an individual's forearm the device is able to detect abnormal concentrations of AGEs. After the subject places the