A panel of experts discussed recent and emerging findings supporting the utility of time in range as an important metric to be considered when determining diabetes treatment and management strategies in the Saturday, June 4, session, Is Time in Range the Gold Standard in Glucose Management?
The session was livestreamed and can be viewed on-demand by registered meeting participants at ADA2022.org. If you haven’t registered for the 82nd Scientific Sessions, register today to access the valuable meeting content.
Roy Beck, MD, PhD, Medical Director of the Jaeb Center for Health Research in Tampa, FL, discussed time in range and glycemic variability and its relationship to vascular diabetic complications.
“We know about the relationship of A1C to risk of retinopathy, nephropathy, and neuropathy,” Dr. Beck said. “And since time in range is strongly associated with A1C and since A1C is strongly associated with complications, it follows that time in range is also associated with complications.”
Findings from recent studies appear to back that up.
“An analysis of DCCT (Diabetes Control and Complications Trial) 7-point blood glucose data as well as a number of cross-sectional and longitudinal studies provide compelling evidence to support the association of time in range with microvascular complications, cardiovascular disease, and mortality,” Dr. Beck said. “Additionally, time in range is influential on quality of life and higher time in range has been associated with more positive mood in people with type 1 diabetes, but further studies are needed.”
Grazia Aleppo, MD, Professor of Medicine (Endocrinology) at Northwestern University Feinberg School of Medicine, discussed the role of time in range in clinical practice.
“We all know that A1C is a biomarker reflecting long-term, retrospective glycemia in diabetes, and it is also the gold standard diabetes outcome metric since DCCT,” Dr. Aleppo said. “And while A1C is an established predictor of diabetes-related complication risk, it does not provide information about timing of hypoglycemia or hyperglycemia and glycemic variability.”
Time in range, on the other hand, is responsive to changes in short-term diabetes management and offers an immediate, flexible way to view glycemic status, she said.
“This allows personalization of diabetes management,” Dr. Aleppo said. “Time in range is not a surrogate for A1C, but they are complementary. A1C is still a useful metric for longer term glycemia, but time in range is a key metric of glucose levels quality and hyperglycemia magnitude. Moving forward, I believe time in range should be included as standard of care in outcome clinical trials.”
Natalie Bellini, MSN, FNP-BC, CDE, Endocrinology Family Nurse Practitioner at R&B Medical Group, Williamsville, NY, talked about how to interpret time in range data and incorporate it into diabetes management alongside continuous glucose monitoring (CGM).
“As we look at CGM data, we want to look at active wear time, how long is the patient wearing it,” she said. “The bare minimum that we really want to make clinical decisions around tends to be at least 70% wear time.”
When interpreting the data and discussing with patients, Bellini said it’s important to focus on the positive.
“When you identify trends, whether they are higher time in range days or lower time in range days, it needs to be in collaboration with the patient,” she said. “We want to gather insight into their foods and their blood glucoses. And when it comes to optimization of the CGM itself, we need to set the parameters that make sense for the patient’s average glucose when you’re starting them, and then slowly bring those parameters down.”
Irl B. Hirsch, MD, Professor of Medicine and Diabetes Treatment and Teaching Chair at the University of Washington, discussed the customization of time in range and the value of individualizing glucose targets.
“You can’t just look at time in range by itself in a silo,” Dr. Hirsch said. “One needs to understand an individual’s time below range in conjunction, and time above range will be the difference. You have to look at the entire package.”
In people with type 1 diabetes, however, he said that neither A1C nor time in range by itself predict severe hypoglycemia. Glycemic risk index (GRI), a new composite metric to assess glycemic control, may be a useful complement to time in range and A1C.
“For now, GRI is based only on adult, otherwise non-frail patients. It needs to be tested to see how it works on other populations of patients, but my hope is that it will become part of the standard CGM download,” Dr. Hirsch said.