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Using CGM Provides Less Staff Exposure To COVID-19

May 15, 2021
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Laura Martínez López, PharmD. Candidate 2021, Lake Erie College of Osteopathic Medicine, College of Pharmacy

Continuous glucose monitoring (CGM) in ICU patients can provide unique benefits to both patients and frontline healthcare workers.  

Blood glucose monitoring is an essential component in the therapy for patients with diabetes mellitus. Monitoring the blood glucose gives the patients an option to adjust in their day-to-day diets, and for healthcare specialists to make changes in therapy. Data suggest that patients can obtain better glycemic control with a higher frequency of blood glucose readings. Pricking your fingers can be uncomfortable over time, and the idea of writing down every single glucose reading to bring the log for the next appointment can be discouraging. Continuous Glucose Monitoring Devices (CGM) can help these patients, offering a significant number of advantages over self-monitoring of blood glucose. CGM can automatically monitor patients’ blood sugar every few minutes, during the day and while they’re asleep. The blood glucose readings are reported in separate reader devices and phones, to family members and healthcare specialists. Recent studies have supported their efficacy, and the practice of using them has become more widely established.  


Last year, when the COVID-19 pandemic started, healthcare professionals expressed concerns about blood glucose monitoring in patients admitted to the hospital. The frontline healthcare workers in the hospitals were concerned about measuring the patient’s blood glucose while protecting their health and well-being during the pandemic. The protocols of fingerstick glucose monitoring for patients in IV insulin drips are site-dependent, but most of them require glucose readings every hour to avoid a hypoglycemia event. During the COVID-19 pandemic, hospitals need personal protective equipment (PPE) to care for the patients. In April 2020, the Food and Drug Administration allowed the use of CGM devices in hospitalized patients. From that moment on, some sites around the country had adopted the use of CGM in their practice by incorporating the apparatus and performing the appropriate training to make the staff feel comfortable using the new technology. This new practice allowed the sites to minimize the use of PPE while providing the best care to the patients.  

Some trials have analyzed the accuracy of CGM in hospitalized patients; discussions arose around determining the use of CGM in ICU patients versus non-ICU patients. From the data reported in these studies, the participants were non-ICU patients. These trials showed that CGM was accurate and beneficial in monitoring blood glucose levels. Also, the devices help detect hypoglycemia and hyperglycemia events. The results are promising for healthcare workers since they can keep safely managing glycemia while reducing PPE use.   

A recent retrospective analysis includes patients in the ICU at Montefiore Medical Center during the COVID-19 pandemic, making it the first trial including critically ill patients in the ICU unit. The study included 11 patients with multiple glucose readings of >180 mg/dL or <70 mg/dL hospitalized in the ICU unit during April and May of 2020 and who were using pressors, were mechanically ventilated, or were receiving renal replacement treatment. The mean age of participants was 56 years, and the mean HgA1C was 8.7. The study calculated the mean and medium average relative difference (MARD and median ARD) between measurements. They measured the point-of-care (POC) once daily and when the CGM device presented hypoglycemic and hyperglycemic alerts.  

The study reported that the MARD was 12.58%, while the median ARD was 6.3%. They said the accuracy obtained during the analysis as zone A – zone E. Zone A represented a CGM within 20% of POC, and 77.7% of the values fell within this zone. On the other hand, 20.5% of the values corresponded to Zone B, which represented a difference greater than 20% with no incorrect treatment. The trial obtained a low percentage of the values (0.2%-0.4%) for zones C, D, and E.  

A great strength of this study was that they include patients with multiple critical illnesses and therapies that make it the first study of this class. On the other hand, the small sample size was a significant limitation of the study. As an overall interpretation, researchers should consider evaluating the actual benefit and the improvements in health these devices offer. This trial provides evidence that the real-time CGM can be used safely in the ICU unit to avoid exposure of the hospital staff.  

Practice Pearls:  

  • CGM systems measure glucose levels around the clock and alert patients and healthcare teams when hypoglycemia is about to occur.  
  • CGM systems can offer an indirect protective effect in health exposure for frontline healthcare workers and reduce potential exposure for COVID-19.  
  • The use of CGM can facilitate the determination of the optimal treatment for blood glucose. 


Agarwal, Shivani, et al. Continuous Glucose Monitoring in the Intensive Care Unit During the COVID-19 PandemicDiabetes Care (2021) 

Ehrhardt, Nicole et al. “The Impact of COVID-19 on CGM Use in the Hospital”. Diabetes Care (2020). 43:2628-2630. November 2020.  

Davis, Georgia et al. Remote Continuous Glucose Monitoring with a Computerized Insulin Infusion Protocol for Critically Ill Patients in a COVID-19 Medical ICU: Proof of Concept Diabetes Care. February 2021.  


Laura Martínez López, PharmD. Candidate 2021, Lake Erie College of Osteopathic Medicine, College of Pharmacy