Use of a Continuous Glucose Monitoring System in High-Risk Hospitalized Noncritically Ill Patients With Diabetes After Cardiac Surgery and During Their Transition of Care From the Intensive Care Unit During COVID-19: A Pilot Study

Endocr Pract. 2022 Jun;28(6):615-621. doi: 10.1016/j.eprac.2022.03.001. Epub 2022 Mar 8.


Objective: Continuous glucose monitoring (CGM) has demonstrated benefits in managing inpatient diabetes. We initiated this single-arm pilot feasibility study during the COVID-19 pandemic in 11 patients with diabetes to determine the feasibility and accuracy of real-time CGM in patients who underwent cardiac surgery and whose care was being transitioned from the intensive care unit.

Methods: A Clarke error grid analysis was used to compare CGM and point-of-care measurements. The mean absolute relative difference (MARD) of the paired measurements was calculated to assess the accuracy of CGM for glucose measurements during the first 24 hours on CGM, the remaining time on CGM, and for different chronic kidney disease (CKD) strata.

Results: Overall MARD between point-of-care and CGM measurements was 14.80%. MARD for patients without CKD IV and V with an estimated glomerular filtration rate (eGFR) of ≥20 mL/min/1.73 m2 was 12.13%. Overall, 97% of the CGM values were within the no-risk zone of the Clarke error grid analysis. For the first 24 hours, a sensitivity analysis of the overall MARD for all patients and those with an eGFR of ≥20 mL/min/1.73 m2 was 15.42% ± 14.44% and 12.80% ± 7.85%, respectively. Beyond the first 24 hours, overall MARD for all patients and those with an eGFR of ≥20 mL/min/1.73 m2 was 14.54% ± 13.21% and 11.86% ± 7.64%, respectively.

Conclusion: CGM has shown great promise in optimizing inpatient diabetes management in the noncritical care setting and after the transition of care from the intensive care unit with high clinical reliability and accuracy. More studies are needed to further assess CGM in patients with advanced CKD.

Keywords: Clark error grid (CEG) analyses; cardiac surgery; chronic kidney disease (CKD); continuous glucose monitoring (CGM); mean absolute relative difference (MARD); noncritically ill.

MeSH terms

  • Blood Glucose
  • Blood Glucose Self-Monitoring
  • COVID-19*
  • Cardiac Surgical Procedures*
  • Diabetes Mellitus*
  • Humans
  • Intensive Care Units
  • Pandemics
  • Patient Transfer
  • Pilot Projects
  • Renal Insufficiency, Chronic*
  • Reproducibility of Results


  • Blood Glucose