Significance of the CGM metric of time in range in children and adolescents with type 1 diabetes

Abstract

Continuous glucose monitoring (CGM) has been widely used in children and adolescents as well as adults with type 1 diabetes. CGM metrics include three key measurements of target glucose: time in range (TIR: 70–180 mg/dL), time below range (TBR: <70 mg/dL), and time above range (TAR: >180 mg/dL). The primary goal of optimal glycemic control is to increase TIR to more than 70%, while simultaneously reducing TBR to less than 4%, while minimizing severe hypoglycemia to less than 1%, as proposed by the Advanced Technologies and Treatments for Diabetes (ATTD) panel. However, several studies have indicated that the TIR goal is quite difficult to achieve in pediatric patients who have remarkable interindividual and day-to-day glycemic variation due to their irregular lifestyles. Previous studies have demonstrated that patients without an automated insulin delivery system are unlikely to attain the recommended glycemic goals. On the other hand, reduction of hypoglycemia, particularly minimizing severe hypoglycemia, is a critical issue in the effective management of children with type 1 diabetes. Frequent episodes of severe hypoglycemia and hypoglycemia can cause lasting neurological damage. Accordingly, we propose reducing the TBR to less than 5%, rather than just targeting the TIR to more than 70%. In CGM metrics this should be the cardinal glycemic goal for pediatric patients who are either being treated with multiple daily injections of insulin or a conventional insulin pump, but who are not using an automated insulin delivery system.