target time in range (TIR) in diabetes

Last edited 07/2022 and last reviewed 08/2022

Continuous glucose monitoring (CGM) allows percentage of readings and time per day within target glucose range (TIR), time below target glucose range (TBR), and time above target glucose range (TAR) (1)

• consensus suggests glycemic cutpoints (a target range of 70-180 mg/dL [3.9-10.0 mmol/L] for individuals with type 1 diabetes and type 2 diabetes and 63-140 mg/dL [3.5-7.8 mmol/L] during pregnancy
  
  
• TIR (70-180 mg/dL [3.9-10.0 mmol/L]) of 70% and 50% strongly corresponded with an A1C of approximately 7% (53 mmol/mol) and 8% (64 mmol/mol), respectively
  
  
• an increase in TIR of 10% (2.4 h per day) corresponds to a decrease in A1C of approximately 0.5% (5.0 mmol/mol)
  
  
• in a trial women with type 1 diabetes, who were randomly assigned women during early pregnancy or planning pregnancy to receive either real-time CGM or standard capillary glucose monitoring (2)
  • found a small but significant reduction in HbA1c levels at 34 weeks' gestation, accompanied by an increased time in target, reduced hyperglycaemia, and less glycaemic variability
  • was accompanied by reductions in neonatal outcomes in the proportion of infants large for gestational age, neonatal hypoglycaemia, admission to neonatal intensive care for more than 24 h, and a 1-day shorter hospital stay among infants of mothers randomly assigned to CGM during the first trimester.

Reference:

• Battelino T, Danne T, Bergenstal RM, Amiel SA, Beck R, Biester T, Bosi E, Buckingham BA, Cefalu WT, Close KL, Cobelli C, Dassau E, DeVries JH, Donaghue KC, Dovc K, Doyle FJ 3rd, Garg S, Grunberger G, Heller S, Heinemann L, Hirsch IB, Hovorka R, Jia W, Kordonouri O, Kovatchev B, Kowalski A, Laffel L, Levine B, Mayorov A, Mathieu C, Murphy HR, Nimri R, Nørgaard K, Parkin CG, Renard E, Rodbard D, Saboo B, Schatz D, Stoner K, Urakami T, Weinzimer SA, Phillip M. Clinical Targets for Continuous Glucose Monitoring Data Interpretation: Recommendations From the International Consensus on Time in Range. Diabetes Care. 2019 Aug;42(8):1593-1603.
• Feig DS, Donovan LE, Corcoy R, et al..; CONCEPTT Collaborative Group . Continuous glucose monitoring in pregnant women with type 1 diabetes (CONCEPTT): a multicentre international randomised controlled trial. Lancet 2017;390:2347-2359