Scientists at UT Southwestern Medical Center in Dallas have discovered that Random Blood Glucose (RBG) values found in testing where the clinician is unaware of the patient’s last food intake, account for most glucose tests performed in clinical practice. Currently, glucose testing guidelines don’t specify using RBG values as part of the diabetes test screening protocol do not flag higher glucose levels as a diabetes risk indicator.
However, a UTSMC research team, led by UT Southwestern Assistant Professor of Internal Medicine, Clinical Sciences, and Pediatrics Dr. Michael Bowen, who is also lead author of a new study published in The Journal of Clinical Endocrinology & Metabolism, says they should.
The study, entitled “Random Blood Glucose: A Robust Risk Factor For Type 2 Diabetes“ (The Journal of Clinical Endocrinology & Metabolism), is coauthored by Michael E. Bowen of the Division of General Internal Medicine, Department of Medicine, University of Texas Southwestern Medical Center at Dallas, along with senior author Dr. Ethan Halm, Professor of Internal Medicine and Clinical Sciences, and Director of the UT Southwestern Center for Patient-Centered Outcomes Research, who holds the Walter Family Distinguished Chair in Internal Medicine in Honor of Albert D. Roberts, M.D; and contributing authors Dr. Lei Xuan, a biostatistical consultant in Clinical Sciences; and Dr. Ildiko Lingvay, Associate Professor of Internal Medicine and Clinical Sciences.
The coauthors note that although random blood glucose (RBG) values are commonly measured in clinical practice, the activity of elevated RBG values as a type 2 diabetes risk factor for is only hazily described.
The objective for this Cross-sectional study of 13,792 non-fasting NHANES participants in the 2005-2010 National Health and Nutrition Examination Surveys, which tested participants for diabetes as part of the survey, was to examine the association between random blood glucose and a patient’s diabetes status in patients without diagnosed diabetes in order to determine non-diagnostic RBG values as a risk factor for type 2 diabetes. Primary Outcomes were: glycemic status (normal glycemia, undiagnosed prediabetes, or undiagnosed diabetes) using hemoglobin HbA1C as the criterion standard.
The researchers investigated multinomial logistic regression examined associations between diabetes risk factors and RBG values according to glycemic status. Additionally, associations between current US screening strategies and a hypothetical RBG screening strategy with undiagnosed diabetes were examined.
The team found that in unadjusted analyses, a single RBG100 mg/dL (5.6 mmol/L) was more strongly associated with undiagnosed diabetes than any single risk factor [Odds Ratio (95% CI) 31.2 (21.3 45.5)] and remained strongly associated with undiagnosed diabetes [20.4 (14.0 29.6)] after adjustment for traditional diabetes risk factors, and that as a hypothetical screening strategy, elevated RBG levels were more strongly associated with undiagnosed diabetes than are current USPSTF guidelines (hypertension alone; p<0.0001) and similar to ADA guidelines (p=0.12).
Based on these findings, the researchers conclude that a single RBG 100 mg/dL is more strongly associated with undiagnosed diabetes than are traditional risk factors, and that abnormal RBG values as a diabetes risk factor should be considered in screening guidelines.
“Our results provide compelling evidence that a single, elevated random blood glucose value is a strong risk factor for diabetes,” observes Dr. Bowen, who is the Dedman Family Scholar in Clinical Care at UT Southwestern, in a release. “After adjusting for traditional diabetes risk factors, we found that individuals with a single random glucose value greater than or equal to 100 milligrams per deciliter (mg/dL) were 20-times more likely to have undiagnosed diabetes compared with those whose values were less than 100 mg/dL.”
“We shouldn’t ignore these values. If we do, we are missing an opportunity to identify patients at high risk for diabetes,” Dr. Bowen continues.
Subjects presenting even modestly elevated levels of random blood glucose (RBG) of between 100 to 119 milligrams per deciliter (mg/dL), were seven-times more likely to have diabetes, according to the study.
And as that number rose, so did diabetes risk. Subjects with RBG values of 120 to 139 mg/dL were 30-times as likely to have undiagnosed diabetes. Individuals with values under 100 mg/dL serving as a reference point control were not considered at risk.
The American Diabetes Association recommends screening for anyone over age 45, or for persons of any age with a body mass index (BMI) greater than 25 who also they have another risk factor, such as family diabetes history. The U.S. Preventive Services Task Force recommends screening as well for persons with hypertension (high blood pressure).
The three screen tests currently available for diabetes diagnosis are 1) a fasting glucose blood test (a value of 126 mg/dL or higher is considered diagnostic); 2) a hemoglobin A1c blood test; and 3) a glucose tolerance test. Dr. Bowen maintains that “Because the vast majority of patients have random blood glucose values in their electronic medical records, there is an opportunity to utilize existing data to prompt a conversation with the patient about testing for diabetes.”
Funding support or resources for this study came from the UT Southwestern Center for Patient-Centered Outcomes Research, the UT Southwestern National Center for Advancing Translational Sciences, the Dedman Family Scholars in Clinical Care, and the National Institutes of Health.
UT Southwestern Medical Center
The Journal of Clinical Endocrinology & Metabolism
UT Southwestern Medical Center