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ADA 81st Symposium: Comparison of Dexcom G6 Continuous Glucose Monitoring Performance between Abdomen and Upper Arm Placement

Aug 14, 2021
 
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Torré Anderson, II, Fourth Year Doctor of Pharmacy Candidate, Florida A&M University College of Pharmacy and Pharmaceutical Sciences, Institute of Public Health 

Alternative site placement of Dexcom G6 continuous glucose monitor device in upper arm is assessed in the hospital setting.

Point of care glucose monitoring is the current standard of care to evaluate glucose levels in the hospital setting. A bedside point of consideration is performed before meals and at bedtime, every four to six hours for patients not eating or on continuous enteral feeding or matching at meal intake and insulin administration. This approach, however, does not provide a 24-hour glycemic profile or detect nocturnal hypoglycemia. Continuous glucose monitoring (CGM) is an advantageous method of measuring blood glucose because it allows for a 24-hour glycemic profile for individuals in an outpatient setting. Studies show that individuals with type 1 and type 2 diabetes who use continuous glucose monitoring had improved glycemic control. Dexcom G6, a serial glucose monitoring device, is FDA approved for use on the abdomen for outpatient glycemic monitoring. Recent studies on the device have suggested that continuous glucose monitoring is a dependable monitoring method compared to the standard point of care glucose monitoring while inpatient. However, the abdominal placement of the device is not always likely due to surgeries and other medical conditions. There has not been any comparative analysis of Dexcom G6 placed on the upper arm and the abdomen in hospitalized patients.

 

This study aimed to determine the feasibility of upper arm continuous glucose monitoring placement and concordance with the approved abdominal location in non-critically ill patients living with diabetes in the hospital setting. Researchers conducted a prospective observational study with patients from Emory University Hospital Midtown and Grady Memorial Hospital. Study endpoints included differences between placement sites on average blood glucose, time in target range (70-180 mg/dL), time below range (<70 and <54 mg/dL), time above range (>180 and >250 mg/dL), and glycemic variability.

Study participants included hospitalized patients living with diabetes who were 18 years of age or greater. Participants had a Dexcom G6 device placed on their abdomen and upper arm. The devices were blinded to patients and staff, and the device alarms were disabled so that clinicians made adjustments to insulin doses per point of care monitoring. Researchers collected data daily including blood glucose, HbA1c, hypoglycemia, hospital complications. A concordance correlation coefficient was applied to the data to estimate the level of reliability of the site placement of the device.

Researchers analyzed data from 91 hospitalized adults living with diabetes. Patient demographics were evenly dispersed apart from race and diabetes type. More patients were living with type 2 diabetes being analyzed than the number of patients living with type 1 diabetes. The average HbA1c level amongst the cohort was 9.2%. The mean glucose levels for the abdomen and arm were 175.8 mg/dL and 173.1 mg/dL, respectively. Researchers observed a higher time in range within the arm placement site group (60.9 +/- 29) than the abdomen placement site group (58.9 +/- 26.8). The abdomen placement site group also spent more time below the range of <70 mg/dL and <54 mg/dL than the arm placement site group. The abdomen placement site group had a higher time above the range of >180 and >250 mg/dL than the arm placement site group. The continuous glucose monitoring device captured more rates of hypoglycemia in the abdomen placement site group than the arm placement site group. Nocturnal hypoglycemia occurred in 74% of patients, with 42% in the arm placement site group. Prolonged hypoglycemia with a duration of greater than two hours was observed in both monitoring groups, but the rate of occurrence was low and relatively even. Researchers followed the concordance correlation coefficient between the two placement sites to be [0.915 (95% CI: 0.907-0.922)], demonstrating good agreement.

This study shows no clinically significant differences in the glycemic profiles between Dexcom G6 continuous glucose monitor placed in the abdomen and upper arm in hospitalized patients with diabetes. The concordance correlation coefficient indicated good agreement meaning that upper arm continuous glucose monitoring may be a practical alternative approach for individuals who cannot have an abdominal placement. This data is now one of the few studies evaluating the efficacy of alternative placement of continuous glucose monitoring. However, the cohort size limited the study. The study did have a significant minority group, but the representation wasn’t generalizable. Also, the ratio of patients living with type 2 diabetes to those living with type 1 diabetes was skewed, thus not making the study’s results applicable to real-world settings. More research is necessary for the efficacy of continuous glucose monitoring on the arm placement site in hospitalized patients.

Practice Pearls:

  • The concordance correlation coefficient indicated good agreement, meaning that upper arm continuous glucose monitoring may be a promising alternative approach for individuals who cannot have an abdominal placement.
  • Researchers observed higher time in range within the arm placement site group (60.9 +/- 29) than the abdomen placement site group (58.9 +/- 26.8).
  • Results of this study are not clinically significant but have added necessary data to the ongoing study of continuous glucose monitoring.

 

Migdal, L. A et al. “Comparison of Dexcom G6 Continuous Glucose Monitoring Performance between Abdomen and Upper Arm Placement in Hospitalized Patients with Diabetes,” (2021, June). ADA 81st Scientific Sessions. (Requires ADA Symposium login.)

 

Torré Anderson, II, Fourth Year Doctor of Pharmacy Candidate, Florida A&M University College of Pharmacy and Pharmaceutical Sciences, Institute of Public Health