Abstract
TIR (Time in Range) derived from Continuous Glucose Monitoring (CGM) was introduced 2019 with target goal of >70% in glucose ranges from 70–180 mg/dl, with less than 5% spent in hypoglycemia range (<4% for 54–70 mg/dl and <1% for <54 mg/dl), with more tighter range for pregnancy in type 1 diabetes, as well gestational and type 2 diabetes. Glycated HbA1c, as a golden standard for diabetes control helps in diabetes management decisions, predicts diabetic complications and it is relatively cheap to perform. Despite its advantages, HbA1c has several limitations such as: does not address glycemic variability, and hypoglycemic events, as well as it is unreliable in hemoglobinopathies. It is well accepted that glycemic outcomes should be evaluated with both Hba1c and TIRs. TIR of 70–180 mg/dl correlates with HbA1c on an average of 7.0%, but due to its wide range (110 mg/dl), HbA1c can vary from 5.2% to 8.3%. Some of the clinicians have introduced the time in tighter range (TiTR), which presents the glucose levels spent in range from 70–140 mg/dl to improve glycemic outcomes in people with type 1 diabetes treated with automated insulin delivery (AID) systems. TiTR in the nondiabetic population is around 90% (from 88% to 96%) compared to 60% in people with T1D using specific AID systems, with a significantly lower TiTR (<35%) in patients using insulin injections. TiTR presents a greater physiological glucose range than TIR and reaching more that 55% of TiTR is related with HbA1c of 6.5%. TiTR should be considered as a secondary parameter for evaluation on glycemic control in the current clinic settings. More awareness in the diabetes community is needed to accept the concept of TiTR as a regular clinical practice.
