The Changing Landscape of Glycemic Targets: Focus on Continuous Glucose Monitoring

Abstract

Continuous glucose monitoring (CGM) provides comprehensive assessment of daily glucose measurements for patients with diabetes and can reveal high and low blood glucose values that may occur even when a patient's A1C is adequately controlled. Among the measures captured by CGM, the percentage of time in the target glycemic range, or "time in range" (typically 70-180 mg/dL), has emerged as one of the strongest indicators of good glycemic control. This review examines the shift to using CGM to assess glycemic control and guide diabetes treatment decisions, with a focus on time in range as the key metric of glycemic control.

FIGURE 1

A depiction showing how patients with the same A1C value may experience different amounts of TIR.

FIGURE 2

Electronic CGM reports allow for visualization of AGP and key glucose metrics. Reproduced with permission from Kruger et al. Diabetes Educ 2019;45(Suppl. 1):3S–20S (ref. 12).

FIGURE 3

TIR defined. Reference ranges help clinicians guide therapy recommendations.

FIGURE 4

Mean proportions of time spent in glycemic ranges after treatment with exenatide once weekly or placebo, each added to metformin. *P <0.001, treatment difference (exenatide once weekly − placebo) in least-squares mean changes. MET, metformin. Reproduced with permission from Frías et al. (53).