Comparing Implantable and Transcutaneous CGM in Patients with Type 1 Diabetes

Results of a recent crossover provides an overview of the accuracy, efficacy, and acceptance of implantable versus transcutaneous continuous glucose monitoring in patients with type 1 diabetes.

A monocentric randomized crossover study comparing an implantable system against a transcutaneous system, results detail differences in glycemic control and device acceptance as well as psychological outcomes based on system used.

“Our study reveals how different CGM systems affect, under real-life conditions, glycemic control, sensor use and acceptance by patients,” wrote investigators.

As the benefits of continuous glucose monitoring have become apparent as a result of randomized clinical trials and observational studies, research has begun to compare the effects of various continuous glucose monitoring systems against one another. In the current study, a team of investigators from the University of Padova in Italy sought to compare the accuracy, efficacy, and acceptance of implantable and transcutaneous continuous glucose monitoring systems.

To do so, investigators designed their study as a randomized crossover trial comparing the Eversense implantable sensor against the Dexcom G5 transcutaneous sensor over a 12-week period. Outcomes of interest for the study included differences in accuracy, time of continuous glucose monitoring use, adverse events, efficacy, and psychological outcomes. Of note, efficacy was measured as HbA1c, time in range, and time above and below range. Additionally, psychological outcomes were evaluated using the Diabetes Treatment Satisfaction Questionnaire (DTSQ), Glucose Monitoring Satisfaction Survey (GMSS), Hypoglycemia Fear Survey (HFS2), and Diabetes Distress Scale (DDS).

For inclusion in the trial, patients needed to be at least 18 years of age or older and have a diagnosis of type 1 diabetes from at least 1 year prior. Exclusion criteria included episodes of hypoglycemia in the year prior to enrollment, use of medications affecting glucose metabolism, inability to comply with study procedures, and being pregnant.

Investigators determined a minimum sample of 12 participants was required to have an 80% chance of detecting at a standardized effect size of 1.25 in a crossover design at the 5% level. A total of 16 subjects were enrolled in the study, with 8 randomized to the Dexcom G5 system and 8 to the Eversense implantable sensor. This cohort had a mean age of 48.8±10.1 years, a mean HbA1c of 55.8±7.9 mmol/mol, and 13 of the 16 subjects were men.

Upon analysis, results indicated the Dexcom G5 system was used more than the Eversense system. When assessing accuracy of the systems, results suggested the mean absolute relative difference was better with the Eversense system (12.2±11.5 vs 13.1±14.7; P <.001). Further analysis indicated there were no differences found in HbA1c between the study arms.

Investigators noted time in range was increased and time in hyperglycemia was decreased among those using Eversense, but this data was not confirmed by analysis of retrofitted data based on self-monitoring of blood glucose values. Additionally, analysis of psychological outcomes suggested use of Eversense reduced perceived distress among patients with no significant changes observed for the other psychological outcomes included in the study.

“Larger studies are necessary to confirm the influence of each CGM system over glycemic control. This study indicates that CGM characteristics need to be taken into account when a device is prescribed,” wrote investigators.

This study, “Implantable and transcutaneous continuous glucose monitoring system: a randomized cross over trial comparing accuracy, efficacy and acceptance,” was published in the Journal of Endocrinological Investigation.