Accuracy of the Dexcom G6 Continuous Glucose Monitoring System Following Cardiac Surgery

This is a prospective longitudinal study to study the agreement between a novel continuous glucose monitoring system (CGMS) versus current blood glucose monitoring.

Subjects in this study will have their blood glucose measured regularly every 1-3 hours with current methods in the cardiovascular intensive care unit (CVICU), and by point of care glucose using the Accuchek Inform II on the regular floors, and the CGMS at the same time will be captured. Subjects will have measurements taken throughout their stay in the CVICU and on the regular floors.

Study Overview

• Status: Active, not recruiting
• Conditions: Surgery--Complications
• Intervention / Treatment: Device: Dexcom G6 continuous glucose monitor

Detailed Description

Maintaining tight blood glucose control following surgery is imperative to reducing infections and neurologic dysfunction. This requires frequent blood sampling while in the intensive care unit, leading to increased waste of blood and utilizing time and resources to collect samples and wait for results. Additionally, when on the regular floors, frequent point of care fingersticks for glucose levels are needed for therapeutic intervention.

Continuous glucose monitoring systems (CGMS) are now available for ambulatory use in patients with diabetes. The potential of using such a system in the hospital, including during the postoperative critical care setting and upon transfer to the regular floor, may reduce personnel burden, produce rapid results, and decrease blood waste. However, these systems have not yet been validated for hospital use.

This is a prospective longitudinal study to study the agreement between a novel continuous glucose monitoring system (CGMS) versus current blood glucose monitoring.

Subjects in this study will have their blood glucose measured regularly every 1-3 hours with current methods in the CVICU, and by point of care glucose using the Accuchek Inform II on the regular floors, and the CGMS at the same time will be captured. Subjects will have measurements taken throughout their stay in the CVICU and on the regular floors. Agreement and correlation between systems will be calculated, and error will be classified using the Surveillance Error grid. The proportion of errors of at least moderate risk will be calculated.

Subject characteristics including demographics, comorbidities and baseline disease severity will be summarized using means and standard deviations for continuous measures and frequencies and percentages for categorical factors. To evaluate agreement between methods, concordance correlation coefficients will be calculated, using the method that adjusts for repeated measures as described by King and implemented in software by Carrasco. Analysis will be performed overall, and then stratifying by type of current measure, if the type of measurement varies across settings. Correlations will be calculated using the methods described by Bland and Altman and implemented by Bakdash and Marusich. Differences will also be evaluated for errors according to the Surveillance Error Grid. Rates of moderate or more severe errors will be calculated. For each measure above, 95% confidence intervals will be calculated, accounting for the clustering within subject.. Analyses will be performed using SAS software (version 9.4; Cary, NC) and R software (version 3.5; Vienna Austria).

Glucose readings obtained from the CGMS will be compared with

1. blood glucose from the arterial blood gas (ABG) or peripheral/central venous catheter if arterial catheter not in use (standard of care in CVICU) while patients are in the CVICU
2. fingerstick point of care (POC) glucose when patients are on the regular floors

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Ohio
    • Cleveland, Ohio, United States, 44195
      • Cleveland Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18 years and above
• Planned cardiovascular surgery
• Planned admission to Cleveland Clinic Main Campus J5 or J6 or Q5 cardiovascular ICU (CVICU) post-operatively
• With or without known diabetes; if with known diagnosis of diabetes, diabetes can be type 1, type 2, or secondary

Exclusion Criteria:

• Allergy to the material of the CGMS or the adhesive to be used
• Skin conditions precluding the use of the CGMS
• Pregnancy
• Other conditions that investigators deem inappropriate for the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Dexcom G6 continuous glucose monitor; All patients will have a Dexcom G6 continuous glucose monitor placed pre-operatively. The glucose readings will be collected for 10 days or upon discharge from the ICU and data will be compared with arterial blood glucose readings or venous Accu-Check Inform II glucose readings	Device: Dexcom G6 continuous glucose monitor; Dexcom G6 continuous glucose monitor will be applied to the upper outer arm before cardiovascular surgery. Data will be collected for 10 days or upon discharge from the ICU.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glucose readings from CGM versus from blood	Glucose readings in mg/dL from the Dexcom CGMS will be compared with blood glucose in mg/dL from the arterial blood gas (ABG) or peripheral/central venous catheter	Up to 10 days
Glucose readings from CGM versus point of care glucose	Glucose readings in mg/dL from the Dexcom CGMS will be compared with fingerstick point of care glucose levels in mg/dL	up to 10 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cost comparison of Dexcom CGMS versus blood glucose testing	The cost of the Dexcom CGMS device including the sensor and transmitter will be compared to the cost of measuring glucose from arterial blood gas	Up to 10 days
Cost comparison of Dexcom CGMS versus fingerstick point of care glucose	The cost in US$ of the Dexcom CGMS device including the sensor and transmitter will be compared to the cost in US$ of measuring glucose from point of care fingerstick testing (Accuchek Inform II meter, test strips, and lancets)	Up to 10 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood volume waste by arterial blood gas	Blood sample amounts in milliliters required for measurement of glucose by arterial blood gas	Up to 10 days
Blood volume waste by fingerstick	Blood sample amounts in milliliters required for measurement of glucose by fingerstick	Up to 10 days

Collaborators and Investigators

• Sponsor: The Cleveland Clinic
• Collaborators: DexCom, Inc.
• Investigators: Principal Investigator: M. Cecilia Lansang, MD, MPH, The Cleveland Clinic

Publications and helpful links

General Publications

• King TS, Chinchilli VM, Carrasco JL. A repeated measures concordance correlation coefficient. Stat Med. 2007 Jul 20;26(16):3095-113. doi: 10.1002/sim.2778.
• Carrasco JL, Phillips BR, Puig-Martinez J, King TS, Chinchilli VM. Estimation of the concordance correlation coefficient for repeated measures using SAS and R. Comput Methods Programs Biomed. 2013 Mar;109(3):293-304. doi: 10.1016/j.cmpb.2012.09.002. Epub 2012 Sep 29.
• Bland JM, Altman DG. Calculating correlation coefficients with repeated observations: Part 1--Correlation within subjects. BMJ. 1995 Feb 18;310(6977):446. doi: 10.1136/bmj.310.6977.446. No abstract available.
• Bakdash JZ, Marusich LR. Repeated Measures Correlation. Front Psychol. 2017 Apr 7;8:456. doi: 10.3389/fpsyg.2017.00456. eCollection 2017. Erratum In: Front Psychol. 2019 May 28;10:1201.
• Klonoff DC, Lias C, Vigersky R, Clarke W, Parkes JL, Sacks DB, Kirkman MS, Kovatchev B; Error Grid Panel. The surveillance error grid. J Diabetes Sci Technol. 2014 Jul;8(4):658-72. doi: 10.1177/1932296814539589. Epub 2014 Jun 13.

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2021
• Primary Completion (Actual): January 20, 2024
• Study Completion (Estimated): May 1, 2024

Study Registration Dates

• First Submitted: September 8, 2020
• First Submitted That Met QC Criteria: September 24, 2020
• First Posted (Actual): September 29, 2020

Study Record Updates

• Last Update Posted (Actual): February 8, 2024
• Last Update Submitted That Met QC Criteria: February 7, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Other Study ID Numbers: 20-698

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes