Expanding the horizon of continuous glucose monitoring into the future of pediatric medicine

Abstract

Glucose monitoring has rapidly evolved with the development of minimally invasive continuous glucose monitoring (CGM) using interstitial fluid. It is recommended as standard of care in the ambulatory setting, nearly replacing capillary glucose testing in those with access to CGM. The newest CGM devices continue to be smaller and more accurate, and integration with automated insulin delivery systems has further revolutionized the management of diabetes, leading to successful improvements in care and quality of life. Many studies confirm accuracy and application of CGM in various adult inpatient settings. Studies in adult patients increased during the COVID 19 Pandemic, but despite reassuring results, inpatient CGM use is not yet approved by the FDA. There is a lack of studies in inpatient pediatric settings, although data from the NICU and PICU have started to emerge. Given the exponential increase in the use of CGM, it is imperative that hospitals develop protocols for CGM use, with a need for ongoing implementation research. In this review we describe how CGM systems work, discuss benefits and barriers, summarize research in inpatient pediatric CGM use, explore gaps in research design along with emerging recommendations for inpatient use, and discuss overall CGM utility beyond outpatient diabetes management. IMPACT: Current CGM systems allow for uninterrupted monitoring of interstitial glucose excursions, and have triggered multiple innovations including automated insulin delivery. CGM technology has become part of standard of care for outpatient diabetes management, endorsed by many international medical societies, now with significant uptake, replacing capillary glucose testing for daily management in patients with access to CGM technology. Although CGM is not approved by the FDA for inpatient hospital use, studies in adult settings support its use in hospitals. More studies are needed for pediatrics. Implementation research is paramount to expand the role of CGM in the inpatient setting and beyond.

Fig. 1. CGM accuracy and major advancements over time.

Modified with permission from Bailey et al. The lower the MARD the better the accuracy.

Fig. 2. Continuous glucose monitor and automated insulin delivery system components.

a Continuous glucose monitors include the sensor, which is a very thin filament that is inserted in the subcutaneous tissue and measures interstitial glucose, as well as a transmitter that stores and sends the glucose data to be displayed. The newest generations of CGMs have a disposable sensor and transmitter that are combined in one unit. b The CGM signal travels via bluetooth to the insulin pump. The automated insulin delivery algorithm uses the CGM data to predict future glucose and calculate insulin needs to try to keep glucose in the target range. The insulin pump continuously delivers rapid acting insulin based on the algorithms calculations. c CGM data is sent via Bluetooth to the receiver. The receiver can be a separate unit that is designed to display the CGM data, or can be a mobile app installed on a smartphone. If the receiver is a on a smartphone, the phone can then send the signal and display the same data to “followers”, such as parents or partners of the person living with diabetes. This feature is commonly used by parents when children are in school or with other caregivers. d The CGM and insulin data for the automated insulin delivery system may be displayed on the pump screen, or depending on the system, may be displayed on a mobile phone app. Often, patients use one mobile phone for both the CGM app and the insulin pump app.

Fig. 3

Subcutaneous CGM sideview.

Fig. 4. Continuous glucose monitor data display.

This CGM tracing shows 4 blood glucose measurements (red dots), of which 3 are in a normal glucose range. The black line represents CGM data. However, there are large post-prandial excursions as well as 2 episodes of hypoglycemia that would be missed by the intermittent blood glucose checks. In the situations where the blood glucose checks were normal prior to hypoglycemia, if the patient saw the CGM glucose rapidly falling they may have been able to completely prevent the hypoglycemia.