Continuous glucose monitoring (CGM) systems are safe and effective for measuring glucose levels in hospital settings, especially in times like the current coronavirus disease 2019 (COVID-19) pandemic, according to a commentary published in the Journal of Diabetes Science and Technology.
There are 2 classes of subcutaneous CGM devices available in the United States: factory-calibrated, which do not require calibration with capillary glucose, such as the Abbott FreeStyle® Libre 14 day Flash Glucose Monitoring System and Dexcom G6®; and patient-calibrated CGM systems that require intermittent calibration with capillary glucose, including Medtronic Guardian™ 3 and Enlite™ 2 and Eversense® systems.
As factory-calibrated CGM systems allow real-time glucose monitoring with less frequent fingerstick testing, this technology may minimize the exposure of healthcare workers to patients and decrease the use of personal protective equipment. The US Food and Drug Administration (FDA) issued a nonobjection to in-hospital use of CGM during the COVID-19 pandemic, and along with many other changes and adjustments that were made during the pandemic, these systems have been used in hospitals to remotely monitor glucose levels.
In-hospital use of CGM is most appropriate when frequent glucose monitoring is of significant value, such as in patients with type 1 diabetes; patients on high-dose insulin or multiple noninsulin glucose-lowering medications; patients with a long-standing history of diabetes; patients with significant glucotoxicity secondary to acute infection, new diagnosis of diabetes, or poor glycemic control over a long period of time; and patients with iatrogenic hyperglycemia secondary to glucocorticoid treatment or medical nutrition therapy. Furthermore, CGM may be important for patients with severe COVID-19 and significant insulin resistance, patients on complex insulin regimens, frail patients, patients with risk factors for hypoglycemia, and patients who were using CGM prior to hospitalization.
While there are data supporting the benefits of CGM use in ambulatory patients, limited data are available in intensive care unit (ICU) or non-ICU hospitalized patients, precluding strong recommendations for use.
It is important to recognize factors that may interfere with glucose readings using CGM, such as ascorbic acid (falsely elevated readings), aspirin (falsely lowered readings), and hydroxyurea use. A lead apron placed over the sensor should be considered for x-rays, computed tomography, angiogram, or fluoroscopy, while sensors should be removed for magnetic resonance imaging.
As surgery may adversely affect the accuracy of CGM systems, it is recommended to confirm CGM accuracy by comparing the data with capillary point-of-care glucose measurements.
Additional limitations of CGM systems include risk for infections, skin reactions, allergic reactions to the adhesive, and potential overcall hypoglycemia. The latter is the basis for the recommendation for point-of-care glucose measurement among patients with glucose levels approaching the hypoglycemic target. Point-of-care glucose measurements are also recommended when there is no correlation between the patient’s symptoms and CGM readings. Use of CGM should be avoided in patients with skin infections, anasarca, and those treated with vasoactive drugs.
“We believe that CGM may be on the threshold of becoming a widely accepted form of continuous automated physiologic monitoring in the hospital setting (depending on what future research data will show), and during the pandemic, this technology can be used to immediately address emergent needs when there is a high demand for both nursing staff and [personal protective equipment],” wrote the commentary authors.
Galindo RJ, Aleppo G, Klonoff DC, et al. Implementation of continuous glucose monitoring in the hospital: emergent considerations for remote glucose monitoring during the COVID-19 pandemic [published online June 14, 2020]. J Diabetes Sci Technol. doi:10.1177/1932296820932903