A paper written by Dr. Elizabeth Selvin, a professor in the Johns Hopkins Bloomberg School of Public Health’s department of epidemiology, has prompted revised clinical guidelines for how diabetes is diagnosed in the U.S. The paper, “Prognostic Implications of Single-Sample Confirmatory Testing for Undiagnosed Diabetes: A Prospective Cohort Study”, appeared online June 19, 2018, in the journal Annals of Internal Medicine.
The study found evidence that a positive result for two standard diabetes markers in a single blood sample is a highly accurate predictor of diabetes and of major diabetes complications such as kidney disease and heart disease. This meant that the earlier standard practice of repeating blood tests to diagnose type 2 diabetes could be avoided in many patients. Because of these findings, the new 2019 American Diabetes Association (ADA) Standards of Care now supports this revised approach to diagnosing diabetes, using a combination of A1C and fasting glucose in a single blood sample.
About 25 million Americans have type 2 diabetes, which involves a failure of the body’s normal regulation of sugar (glucose) levels in the blood. The resulting chronic elevation of blood glucose (hyperglycemia) increases the risk of other major illnesses including heart disease, eye disease, kidney disease, and stroke.
The earlier clinical guidelines recommend that an initial blood test result indicating elevated fasting levels of glucose or glycated hemoglobin (HbA1c) be confirmed at a second doctor’s visit with another blood test—a time-consuming and relatively expensive practice that could lead to missed diagnoses.
Under the new guidelines, if patients have both an elevated fasting glucose and an elevated HbA1c in a single blood sample, a diagnosis of diabetes can be made immediately. For those patients where one test is elevated, but not the other, a follow-up visit may be warranted, consistent with existing guidelines.
Dr. Selvin’s paper was cited as one of the “Best of 2018” in Annals. Hopkins co-authors include Ms. Dan Wang, a biostatistician in the Bloomberg School’s department of epidemiology, Dr. Josef Coresh, George W. Comstock Professor in the Bloomberg School’s department of epidemiology, Dr. Kunihiro Matsushita, associate professor, the Bloomberg School’s department of epidemiology and Dr. Morgan E. Grams, associate professor, Johns Hopkins School of Medicine and the Bloomberg School’s department of epidemiology.