Prediction Quality of Glucose Trend Indicators in Two Continuous Tissue Glucose Monitoring SystemsParts of these data were previously presented at the 53rd Annual Meeting of the European Association for the Study of Diabetes, September 11–15, 2017, Lisbon, Portugal.

Abstract

Background: Continuous interstitial glucose monitoring (CGM) systems often provide glucose trend indicators (e.g., arrows) in addition to current glucose values. These indicators are recommended to be used in therapeutic decisions, because they are ascribed predictive qualities by CGM system manufacturers and expert committees. This study assessed how reliably trend indicators match future glucose change, because such information is missing.Methods: In a clinical trial, two different CGM systems were used by 20 participants, with two sensors of each system per patient. Participants used the systems for 14 days with three study site visits (48 h each). During study site visits, glucose trend indicators, as displayed by the CGM systems, were recorded at least once per hour during daytime and once at night in a diary. In addition, CGM data were downloaded from the devices.Trend indicators were compared with glucose change calculated from CGM data >30 min after recording the trend indicator.Results: Approximately 60% of trend indicators matched the glucose change calculated from CGM data. More than 10% of trend indicators differed by at least two trend indicator categories. Focusing on trend indicators recorded around carbohydrate (CHO) intake and insulin deliveries resulted in approximately half of trend indicators matching the calculated glucose change.Conclusions: Trend indicators do not always match future glucose change, especially within the first few hours after CHO intake and insulin deliveries. Manufacturers' labeling and recommendations should reflect this, so that CGM users can make informed decisions.

Effectiveness of Using the FreeStyle Libre® System for Monitoring Blood Glucose during the COVID-19 Pandemic in Diabetic Individuals: Systematic Review

“…FSL is a simple device, and consists of two components: a disposable sensor, which is inserted into the user’s upper arm, and a touchscreen device/reader, which is used to scan and retrieve other continuous glucose monitoring (CGM) readings [ 23 ]. FSL has been an important tool for patients with T2DM [ 24 ], with additional advantages for this population, which is considered a high-risk group for infectious diseases, whereby individuals with insulin resistance have a 50–60% higher risk of pulmonary infection [ 25 ].…”

Predictive Glucose Trends From Continuous Glucose Monitoring: Friend or Foe in Clinical Decision Making?

“…Recently, intriguing data questioning the accuracy of ROC indicator arrows on both the Dexcom G5 and Freestyle Libre systems was published by Freckmann et al They reported that ROC trend arrows match measured tissue glucose change in only approximately 60% of cases. 12 Of most concern is that in over 10% of cases, particularly around the time of carbohydrate ingestion and insulin administration, ROC trend projection fidelity with measured glucose was remarkably poor. While the relative sensor inaccuracy in the initial 12-24 hours of CGM wear that we are familiar with was again borne out in this study, of significant concern is that even with prolonged multiday use, sensor-derived glucose trends varied from calculated glucose trends based on fingerstick glucose measurements by 2 or more trend indicator categories 10% of the time.…”

“…To add further complexity, ROC arrows have different appearances and meanings across different devices, and more recent literature has suggested that ROC trend arrows may not be a very reliable marker of future glucose change. 12…”

National Consensus in the use of the Flash Glucose Monitoring System in Portugal

“…28 The first postprandial hours and after insulin administration seem to be the moment where there may be less precision. 29 The precision of the two different systems -Dexcom G5 and FreeStyle Libre -seem to be similar. 30 The recommendations that existed until now, briefly discussed below, are essentially based on the experience of experts, of people with diabetes, and on the few available clinical studies.…”