Accuracy of the Dexcom G6 Glucose Sensor during Aerobic, Resistance, and Interval Exercise in Adults with Type 1 Diabetes

Abstract

The accuracy of continuous glucose monitoring (CGM) sensors may be significantly impacted by exercise. We evaluated the impact of three different types of exercise on the accuracy of the Dexcom G6 sensor. Twenty-four adults with type 1 diabetes on multiple daily injections wore a G6 sensor. Participants were randomized to aerobic, resistance, or high intensity interval training (HIIT) exercise. Each participant completed two in-clinic 30-min exercise sessions. The sensors were applied on average 5.3 days prior to the in-clinic visits (range 0.6–9.9). Capillary blood glucose (CBG) measurements with a Contour Next meter were performed before and after exercise as well as every 10 min during exercise. No CGM calibrations were performed. The median absolute relative difference (MARD) and median relative difference (MRD) of the CGM as compared with the reference CBG did not differ significantly from the start of exercise to the end exercise across all exercise types (ranges for aerobic MARD: 8.9 to 13.9% and MRD: −6.4 to 0.5%, resistance MARD: 7.7 to 14.5% and MRD: −8.3 to −2.9%, HIIT MARD: 12.1 to 16.8% and MRD: −14.3 to −9.1%). The accuracy of the no-calibration Dexcom G6 CGM was not significantly impacted by aerobic, resistance, or HIIT exercise.

A Comprehensive Review of Continuous Glucose Monitoring Accuracy during Exercise Periods

“…Fourteen patients were monitored during six days of mountain biking activity, using the Guardian-Connect and the FreeStyle Libre sensor, reporting a higher MARD than other studies for the exercise period, with values of 29% and 22%, respectively. On the other hand, Guillot et al [ 68 ], which is also a recent study, presented a lower MARD for the three types of exercise, using the Dexcom G6 and SMBG to calculate the CGM accuracy.…”

“…Those that used FreeStyle Libre were already factory-calibrated, for example Giani et al [ 6 ] and Aberer et al [ 37 ]. Some articles did not specify the calibration method used, like Moser et al [ 55 ], Williams et al [ 63 ], Fokkert et al [ 67 ] and Guillot et al [ 68 ].…”

“…Another method [ 76 ] for obtaining the SD is to use the Confidence Interval (CI) values provided: , N being the number of samples. This method was applied for the case of Guillot et al [ 68 ]. In that same article, only the median value for the absolute relative difference of the rest samples was reported.…”

“…It is remarkable to find a lack of new-generation sensors used in exercise studies, such as Dexcom G5 or G6, even in more recent studies, when they present improved accuracy compared to previous generations according to the manufacturers. Zaharieva et al [ 54 ] and Guillot et al [ 68 ] are the only studies that provided MARD values using Dexcom G5 (MARD exercise 13%) and Dexcom G6 (MARD exercise 13.3%, 13% and 12.4%), respectively.…”

Continuous glucose monitoring in an end‐stage renal disease patient with diabetes receiving hemodialysis

“…As a 2020 Kidney Disease Improving Global Outcomes “Practice Point” (i.e., guidelines in which there is limited evidence and further research is needed), in scenarios where HbA1c accuracy may be uncertain CGM may be used, and CGM metrics such as time‐in‐range and time‐in‐hypoglycemia may be considered as alternatives to HbA1c for defining glycemic targets 9 . Notably, in patients with type 1 and 2 diabetes without CKD, the Dexcom G6 CGM has shown good agreement with blood glucose (based on metrics such as the median absolute relative difference, median relative difference, and Clarke error grid analysis) 30,31 …”