The American Diabetes Association (ADA) in its 2018 Standards of Medical Care in Diabetes is recommending continuous glucose monitoring (CGM) to all adults 18 and over who aren’t meeting glycemic targets, as well as screening high-risk youths for type 2 diabetes. The revised guidelines, published in Diabetes Care, also created new specifications for applying the HbA1c (A1C) test.
“Since 1989, the American Diabetes Association has provided annual updates to the Standards of Care, and the Standards are accepted as the global standard for diabetes care,” said ADA’s Chief Scientific, Medical and Mission Officer William T. Cefalu, MD, in a statement. ADA plans on updating this document throughout the year in light of new technology, research, and therapy developments, Cefalu said.
Two sections in this guidance—classification and diagnosis of diabetes and glycemic targets—specifically address the limitations of A1C measurements. A number of different factors can affect the results of this test, including assay interference, hemoglobin variants, and variations in red blood cell turnover rates, as well as age, pregnancy, and ethnicity. ADA clarified how A1C should be used to help diagnose and monitor diabetes, recommending that clinicians use alternatives such as fasting plasma glucose or oral glucose tolerance tests in the event that A1C results and blood glucose levels don’t agree.
The guidance suggested that A1C testing take place just twice a year in patients who are successfully managing their diabetes, compared with those not meeting glycemic goals or who have experienced changes in their therapy. For these patients, A1C testing should take place quarterly. “Point-of-care testing for A1C provides the opportunity for more timely treatment changes,” the authors recommended.
ADA’s 2018 update also refines screening recommendations for certain populations. As an example, the document recommends type 2 screening in children and adolescents younger than age 18 who qualify as overweight or obese with body mass index >85th percentile for age and sex, weight for height >85th percentile, or weight >120% of ideal for height and one or more additional risk factor(s). The latter include: family history of type 2 diabetes in first or second degree relatives; any history of diabetes during a child’s gestation; Native American, African American, Latino or Asian American Pacific Islander descent; and signs of insulin resistance or conditions associated with insulin resistance such as hypertension or dyslipidemia.
ADA previously recommended that CGM take place in adults 25 years or older with type 1 diabetes. In the revised guidance, the organization took new data in account, expanding CGM to all adults who are unable to meet glycemic targets.
The 2018 standards also include language about new CGM technology, highlighting a newly approved “flash” CGM device for adults that provides on-demand glucose readings. “A study in adults with well-controlled type 1 diabetes found that flash CGM users spent less time in hypoglycemia than those using [self-monitoring of blood glucose]. However, due to significant differences between flash CGM and other CGM devices, more discussion is needed on outcomes and regarding specific recommendations,” according to the guideline authors.
ADA provided additional information about devices that no longer require confirmation from fingerstick testing to make treatment decisions. It also modified language to align with recent data showing that CGM helps improve glycemic control for adults with type 1 diabetes.