This is an update from a 2008 recommendation that only mentioned hypertension.
The United States Preventative Services Task Force (USPSTF) has updated a 2008 recommendation about blood glucose screening in adults. Previously, they recommended screening adults between the ages of 40 and 70 years old with hypertension; this release did not mention weight. In an update of that recommendation published this month, the USPSTF has changed the recommendation to screen for the disease in adults between those ages who are overweight or obese. The change comes as the prevalence of both obesity and T2DM continue to grow in the United States. Being overweight is a major risk factor for T2DM.
The USPSTF recommendation notes that increased blood sugar contributes to cardiovascular disease, the number one cause of death in the United States. It is important to identify adults with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) – while these conditions do not always lead to full T2DM, up to 30% of adults with IFG or IGT will develop T2DM within five years, absent lifestyle changes. These conditions are also strongly correlated with other metabolic disorders such as hyperlipidemia and hypertension.
According to the USPSTF recommendation, the benefits of early impaired glucose metabolism detection outweigh the downsides. Benefits include improvements in mortality and morbidity, and reduction in progression to T2DM. Patients with IFG or IGT who undergo appropriate lifestyle interventions have been proven to have moderate reductions in disease progression. Lifestyle intervention is noted to have a bigger effect on disease progression than medication such as metformin. The downsides of early detection is primarily anxiety in the short-term, but no proven long-term psychological problems. In addition, lifestyle interventions have little to no adverse effects; pharmacological intervention for IFG or IGT can have up to moderate harm, depending on the drug and dosage.
According to the USPSTF recommendation, IFG and IGT should be screened for with three tests: Hemoglobin A1c, fasting plasma glucose level, and the oral glucose tolerance test. A normal hemoglobin A1c is < 5.7%; IFG or IGT is identified with an A1c of 5.7-6.4%, while T2DM shows a level of 6.5% or higher. Normal fasting plasma glucose is less than 100 mg/dl; a level of 100 to 125 mg/dl reveals IFG or IGT, and a level greater than 126 mg/dl indicates T2DM. A normal oral glucose tolerance test will read at 139 mg/dl or lower. A blood glucose level of 140-199 mg/dl after the test indicates IFG or IGT, and a level greater than 200 mg/dl indicates T2DM. Repeat testing with the same test on a different day is encouraged for confirmation. Patients found to have IFG or IGT should undergo counseling for intensive lifestyle interventions including increased physical activity and changes to diet. Screening is recommended every 3 years for adults with normal glucose levels.
- The USPSTF recommends screening all overweight adults between the ages of 40 and 70 for glucose metabolism abnormalities.
- Screening is recommended every 3 years for adults with normal blood glucose.
- The benefits of early screening include improvements in cardiovascular outcomes and possible prevention of T2DM disease progression. The downsides are minor and include short-term anxiety.
Siu AL. “Screening for Abnormal Blood Glucose and Type 2 Diabetes Mellitus: U.S. Preventive Services Task Force Recommendation Statement.” Ann Intern Med. 2015; published online 27 October 2015. doi:10.7326/M15-2345.
Comment: In a statement released by the American Diabetes Association, the association expressed disappointment that the recommendations fall short of “well-established screening guidelines of diabetes experts around the world.” The USPSTF recommendation risks missing diabetes in several groups with a high prevalence of undiagnosed disease, including younger adults, certain ethnic groups and women with a history of gestational diabetes. “Diabetes is a serious disease that can result in dangerous, life-threatening complications, including, but not limited to, cardiovascular disease,” Robert Ratner, MD, Chief Scientific and Medical Officer of the association, said in the statement.