Implantable continuous glucose sensor found to be accurate

This study investigated the safety and accuracy of a new implantable continuous glucose monitoring (CGM) sensor. It found that the device was accurate and safe.

CGM systems provide real-time information on glucose levels and reduce the need for fingerstick testing. In CGM systems glucose is measured by a sensor placed in the fat just under the skin. In most systems the sensor is connected to a transmitter that sends data wirelessly to a display device, such as a smartphone.

In the implantable CGM system the sensor is inserted into the upper arm in a minor surgical procedure. The transmitter is placed on the skin, just over where the sensor was inserted, and held in place by an adhesive patch. Currently no long-term data on the accuracy of this type of sensor is available.

This study recruited 71 adults with type 1 or type 2 diabetes. A glucose sensor was implanted into both upper arms of each patient. The patients attended 8 clinic visits to assess the device over the 180 days of the study. During these visits the patient’s blood glucose levels were examined and compared to the reading on the CGM system.

The overall difference between the average blood glucose measured at the clinic and that on the CGM system was 11.6%. This difference was higher, 21.7%, when blood glucose levels were low. The accuracy of the CGM system decreased in the last month of use. 40% of sensors were still functional at day 180. The average life of the sensors was 149 days. HbA1c (average blood glucose over the last 3 months) improved when the implantable CGM sensors were used. HbA1c decreased from an average of 7.54% at the start of the study to 7.19% at the end.

The patients did not report any improvement in quality of life. However, 84% said they would want to use the implanted sensor again. No severe side effects were caused by the device. 

The study concluded that the implantable CGM sensor was accurate and safe over the course of the sensor life.

This study was funded by the manufacturers of the implantable CGM system. Patients with type 2 diabetes were underrepresented in this study, as were non-Caucasian patients. As such, the results may not apply equally to all people with diabetes. Furthermore this study did not examine patients undergoing any other form of glucose-monitoring, for comparison.

Discuss whether the implantable CGM system is suitable for you with your physician.