A Comparison of Time Delay in Three Continuous Glucose Monitors for Adolescents and Adults

Abstract

Background: The physiologic delay in glucose diffusion from the blood to the interstitial fluid and instrumental factors contribute to the delay between changes in plasma glucose (PG) and measurements made by continuous glucose monitors (CGMs). This study compared the duration of this delay for three CGMs. Methods: A total of 24 healthy adolescent and adult subjects with type 1 diabetes wore three CGM devices simultaneously for 48 hours: Dexcom G4 Platinum, Abbott Navigator, and Medtronic Enlite. The time delay between PG and CGM-estimated plasma glucose (CGMG) was estimated by comparing time-shifted CGMG with reference PG taken every 15 minutes. Results: The delay estimated by our approach was larger for the Navigator than for the G4 Platinum in adolescents (7.7 ± 1.1 versus 5.6 ± 0.9 min, P = .0396) and adults (10.9 ± 1.1 versus 8.1 ± 0.7 min, P = .0107). The delay was nominally longer for the Navigator than for the Enlite in both the adolescent (7.7 ± 1.1 versus 4.3 ± 1.0 min, P = .0728) and adult (10.9 ± 1.1 versus 8.3 ± 0.9 min, P = .111) populations, but these differences were not statistically significant. There was no difference in the delay between G4 Platinum and Enlite. Adolescents had shorter delays than adults for all three devices. There was a significant correlation between longer delay and increasing age for the G4 Platinum and Navigator. Conclusions: There are differences in the estimated PG to CGMG time delays between CGM devices in the same subjects. The delay between PG and CGMG is smaller for adolescents than for adults. The PG–to–CGMG time delay is influenced by both instrument and host factors.

The challenges of achieving postprandial glucose control using closed‐loop systems in patients with type 1 diabetes

“…CGMS readings are measured in the interstitial fluid, which can differ from plasma BG due to the time delay needed to equilibrate glucose between the blood vessels and interstitial fluid compartments. The time delay can vary from 3 to 12 minutes and is highest when BG levels are rapidly changing, such is the case post meals or during exercise . These sensor delays remain one of the main challenges faced by CLS algorithms and can affect the efficacy of the artificial pancreas in regards to meals.…”

“…The time delay can vary from 3 to 12 minutes and is highest when BG levels are rapidly changing, such is the case post meals or during exercise. 67,68 These sensor delays remain one of the main challenges faced by CLS algorithms and can affect the efficacy of the artificial pancreas in regards to meals. Other than time delays, CGMS performance can be influenced by calibration errors and delays from patients or from capillary glucose meter values.…”

Data Analysis and Accuracy Evaluation of a Continuous Glucose-Monitoring Device

“…What is more, there was a lag time between the interstitial glucose concentration and the capillary glucose concentration. It showed the delay time distribution at various reference concentrations in Figure 5(a), and the average delay of each patient is shown in Figure 5(b) [16]. As can be seen from the above diagrams, the delay was caused by multiple factors and it was not a stable value in a relatively large range (maximum > 60 minutes).…”

Monitoring of Pediatric Type 1 Diabetes

“…The lag time between blood and sensor glucose values varies depending on individual patient factors, fasted vs. fed state, and activity levels (28)(29)(30). In addition to physiologic lag time, additional delays occur due to the time required for the sensor reaction to detect changes in interstitial glucose concentrations and for signal processing (31,32). There is sparse literature exploring the total duration of lag time.…”