Time in Range (TIR) is a new clinical metric that expresses the percentage of time a person with diabetes spends within their target glycemic range.1 TIR is measured by continuous glucose monitoring (CGM) and may be used with other CGM metrics, including Time Below Range (TBR, which indicates hypoglycemia), Time Above Range (TAR, which indicates hyperglycemia), mean glucose, and glycemic variability to assess a person’s glucose levels.1-3
Time in Range, a new clinical metric for diabetes management.1
Both Diabetes Canada and the International Consensus Report on TIR recommend that most people with type 1 or type 2 diabetes spend at least 70% of the day (around 17 hours) in the target glycemic range of 3.9 to 10 mmol/L, which corresponds to the recommended A1C target of approximately 7% (53 mmol/mol).1,3
Clinical guidance and targets for TIR, TBR and TAR, according to the International Consensus Report.1
TIR is a complement to A1C, the current gold standard for assessing glucose control.1,2,4 For more than three decades, A1C has been relied on as both a diagnostic measure and diabetes management tool for people with diabetes and healthcare professionals.4 Like A1C, TIR has also been associated with reduced risk of developing diabetes-related microvascular and macrovascular complications.5-9 However, while A1C measures a person’s average blood glucose levels over the previous two to three months, it does not reflect daily fluctuations.1 Moreover, it does not capture the variable occurrence of hypoglycemia and hyperglycemia.1 In fact, two people with the same A1C results could have very different glucose profiles.10
An example of two people with the same A1C with different glucose profiles.
TIR, together with TBR and TAR, provides a more complete picture of glucose levels and has the potential to reveal patterns of hypoglycemia and hyperglycemia throughout the day and night. When used in conjunction with A1C, TIR can tell a personalized and individual story about glucose levels, helping people with diabetes to understand both their daily fluctuations and what is driving them, and helping healthcare professionals make more informed decisions for better diabetes management.1