time in range (TIR) 使用連續性血糖偵測時, 血糖在設定範圍內所佔時間比例
15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes—2023
15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes—2023
Continuous Glucose Monitoring in Pregnancy 懷孕期的連續性血糖偵測
CONCEPTT was a randomized controlled trial (RCT) of real-time continuous glucose monitoring (CGM) in addition to standard care, including optimization of pre- and postprandial glucose targets versus standard care for pregnant people with type 1 diabetes. It demonstrated the value of real-time CGM in pregnancy complicated by type 1 diabetes by showing a mild improvement in A1C without an increase in hypoglycemia and reductions in large-for-gestational-age births, length of stay, and neonatal hypoglycemia (44). An observational cohort study that evaluated the glycemic variables reported using CGM found that lower mean glucose, lower standard deviation, and a higher percentage of time in target range were associated with lower risk of large-for-gestational-age births and other adverse neonatal outcomes (45). Use of the CGM-reported mean glucose is superior to the use of estimated A1C, glucose management indicator, and other calculations to estimate A1C, given the changes to A1C that occur in pregnancy (46).
CGM time in range (TIR) can be used for assessment of glycemic outcomes in people with type 1 diabetes, but it does not provide actionable data to address fasting and postprandial hypoglycemia or hyperglycemia. The cost of CGM in pregnancies complicated by type 1 diabetes is offset by improved maternal and neonatal outcomes.
The international consensus on TIR (50) endorses pregnancy target ranges and goals for TIR for people with type 1 diabetes using CGM as reported on the ambulatory glucose profile; however, it does not specify the type or accuracy of the device or need for alarms and alerts. A prospective, observational study including 20 pregnant people with type 1 diabetes simultaneously monitored with intermittently scanning CGM (isCGM) and real-time CGM (rtCGM) for 7 days in early pregnancy demonstrated a higher percentage of time below range in the isCGM group. Asymptomatic hypoglycemia measured by isCGM should therefore not necessarily lead to a reduction of insulin dose and/or increased carbohydrate intake at bedtime unless these episodes are confirmed by blood glucose meter measurements (51). Selection of CGM device should be based on an individual’s circumstances, preferences, and needs.
Target range 63–140 mg/dL (3.5–7.8 mmol/L): TIR, goal >70%
Time below range (<63 mg/dL [3.5 mmol/L]), goal <4%
Time below range (<54 mg/dL [3.0 mmol/L]), goal <1%
Time above range (>140 mg/dL [7.8 mmol/L]), goal <25%
The international consensus on TIR (50) endorses pregnancy target ranges and goals for TIR for people with type 1 diabetes using CGM as reported on the ambulatory glucose profile; however, it does not specify the type or accuracy of the device or need for alarms and alerts. A prospective, observational study including 20 pregnant people with type 1 diabetes simultaneously monitored with intermittently scanning CGM (isCGM) and real-time CGM (rtCGM) for 7 days in early pregnancy demonstrated a higher percentage of time below range in the isCGM group. Asymptomatic hypoglycemia measured by isCGM should therefore not necessarily lead to a reduction of insulin dose and/or increased carbohydrate intake at bedtime unless these episodes are confirmed by blood glucose meter measurements (51). Selection of CGM device should be based on an individual’s circumstances, preferences, and needs.
Target range 63–140 mg/dL (3.5–7.8 mmol/L): TIR, goal >70%
Time below range (<63 mg/dL [3.5 mmol/L]), goal <4%
Time below range (<54 mg/dL [3.0 mmol/L]), goal <1%
Time above range (>140 mg/dL [7.8 mmol/L]), goal <25%
