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Arkansas Geriatric Education Collaborative

Continuous Glucose Monitoring: Potential Benefits in Type 2 Diabetes Mellitus

Summer 2021 Newsletter

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By Madeline Malloy, Doctor of Pharmacy Candidate, and Lisa C. Hutchison, PharmD, MPH, BCPS, BCGP
University of Arkansas for Medical Sciences (UAMS) College of Pharmacy

Type 2 diabetes mellitus (T2DM) is a common condition that is caused by insulin resistance, resulting in an increase in blood glucose levels. Diabetes disproportionately affects adults aged 65 and older with 1 in 4 receiving a diagnosis.1 Stabilizing glucose levels has shown to be increasingly more important in diabetes as there are on-going studies evaluating the association between glucose variability and the development of comorbidities that can have a serious impact on ones’ health including heart disease, kidney disease, and vision loss.2,3

To keep their blood glucose levels in a healthy range, patients must monitor their blood glucose levels and adjust their insulin accordingly.  Through the use of a glucometer and testing with finger sticks,  patients can accurately measure their glucose themselves. However, there are several limitations to self-monitoring blood glucose (SMBG) such as: user error, multiple finger pricks causing decreased compliance, and the quality and stability of the enzymatic test strips.4 An alternative method to measuring glucose levels is through continuous glucose monitoring (CGM), which periodically tracks blood sugar levels at different intervals throughout the day. Monitors used for CGM have the ability to sync up to smartphones and tablets, allowing  patients to see their glucose level in real time, set alarms for instances of hypoglycemia or hyperglycemia, and track meals, activity, and medications aiding a more in-depth analysis of their glucose trends. Some monitors even connect to insulin pumps, administering insulin when needed. For CGM to work, a sensor is placed under the skin typically on the abdomen or on the upper arm. This sensor measures the glucose level within the interstitial fluid, which is found between cells.The patient replaces the sensor every 3 to 7 days depending on the monitor.  In addition, they must calibrate it twice daily, as opposed to 4 – 6 finger sticks per day using SMBG methods.5   

While the use of CGM in type 1 diabetes mellitus (T1DM) is well established, it has yet to become commonplace for T2DM patients who require insulin therapy. Recently, there have been many studies discussing the potential benefits T2DM patients could derive from CGM such as better glycemic control, A1C reduction, and life-style modifications.6

Hypoglycemia is a serious risk for older patients, as it is associated with an increased risk for falls, arrhythmias, cognitive impairment, and even death. A study by Polonsky et al. showed that patients using a CGM reported fewer moderate-to-severe hypoglycemic events over the course of 6 months and greater reductions in hypoglycemic events that necessitated assistance from a caretaker, paramedic, or the ER.7 Both older adults and their caretakers that are burdened with the responsibility of managing diabetes may benefit from the ability to monitor real-time levels and be alerted by hypoglycemic events.

The use of CGM has shown statistically significant differences in A1C reduction  compared to SMBG in T2DM patients. Vigersky et al. performed a study on the effect of CGM in patients with T2DM that were not on prandial insulin. Those randomized to use a CGM intermittently for 12 weeks had an improved A1C at 12 weeks and continued that improvement during the 40-week follow-up compared to those that only used SMBG. The CGM decreased their A1Cs by 1.0, 1.2, 0.8, and 0.8% whereas the SMBG group decrease their A1cs by 0.5, 0.5, 0.5, and 0.2% at 12, 24, 38, and 52 weeks, respectively.8 Ruedy et al. shifted the focus of their study to the effectiveness of CGM in older adults >60 with both T1DM and T2DM on multidose insulin injection therapy (MDI). The results of this study showed a greater A1C reduction (−0.9 ± 0.7% versus −0.5 ± 0.7%, P < .001) and decreased glycemic variability in the CGM group as opposed to the SMBG group. The results of this trial show that while we know CGM is beneficial for T1DM, CGM also aids older patients with T2DM get closer to their goal A1C. 9

In addition, CMG can contribute to patient education and subsequently, behavioral change, helping patients commit to lifestyle modifications and improve blood glucose levels. A systematic review performed by Taylor et al. demonstrated that CGM use was associated with positive lifestyle modifications such as a decrease in body weight and caloric intake, adherence to diet, and increased physical activity compared to SMBG.These studies demonstrate that CGM can help control T2DM in the short term, and in the long term through an improvement in the patient’s lifestyle and adherence to their treatment.6

A literature review showed that in adults, ages 51.7 – 60 years old, CGM supported greater reductions in A1C, bodyweight, and caloric intake, and increased adherence to diet and physical activity. Not only that, but a >90% compliance to CGM wear-time and calibration was reported.10 Ruedy et al. states that satisfaction was high with the CGM, defined as perceived benefits, were high compared to perceived difficulties.9 Polonsky et al. found that regarding  patients’ quality of life, those that used the CGM reported feeling as though they were in a better state of well-being, less fearful of a hypoglycemic event, and less distressed.7 The high praise of the CGM system from these studies could mean that CGM has the potential to reduce burnout in those that are overwhelmed by their disease state management.

Patients with T2DM have similar goals and face similar obstacles in managing their blood glucose as those with T1DM no matter their age, and therefore, could also benefit from continuous glucose monitoring.6 With improvements made in the CGM technology in the future, it seems that CGM may very well become the standard of care to reduce the burden of diabetes management and improve the health outcomes for patients with T2DM.

References:

  1. National Diabetes Statistics Report. 2020. Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/diabetes/pdfs/data/statistics/national-diabetes-statistics-report.pdf.
  2. Ohara, M., Fukui, T., Ouchi, M., Hayashi, T., Oba, K., & Hirano, T. 2016. Relationship between daily and day-to-day glycemic variability and increased oxidative stress in type 2 diabetes. Diabetes Research and Clinical Practice 122: 62 – 70.
  3. What is diabetes? 2020. Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/diabetes/basics/diabetes.html.
  4. Jasha van Enter, B. & von Hauff, E. 2018. Challenges and perspectives in continuous glucose monitoring. Chemical Communications 54: 5032 – 5045.
  5. Continuous Glucose Monitoring. 2017. National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved from https://www.niddk.nih.gov/health-information/diabetes/overview/managing-diabetes/continuous-glucose-monitoring.
  6. Jackson, M.A., Ahmann, A., & Shah, V.N. 2021. Type 2 Diabetes and the Use of Real-Time Continuous Glucose Monitoring. Diabetes Technology & Therapeutics 23: 27 – 34.
  7. Polonsky W.H., Peters A.L., & Hessler D. 2016. The impact of real-time continuous glucose monitoring in patients 65 years and older. Journal of Diabetes Science and Technology 10: 892 – 897.
  8. Vigersky, R.A., Fonda, S.J., Chellappa, M., Walker, M.S., & Ehrhardt, N.M. 2012. Short-and Long-Term Effects of Real-Time Continuous Glucose Monitoring in Patients With Type 2 Diabetes. Diabetes Care 35: 32 – 38.
  9. Ruedy, K.J., Parkin, C.G., Riddlesworth, T.D., & Graham, C. 2017. Continuous Glucose Monitoring in Older Adults With Type 1 and Type 2 Diabetes Using Multiple Daily Injections of Insulin: Results from the DIAMOND Trial. Journal of Diabetes Science and Technology 11(6): 1138 – 1146.
  10. Taylor, P.J., Thompson, C.H., & Brinkworth, G.D. 2018. Effectiveness and acceptability of continuous glucose monitoring for type 2 diabetes management: A narrative review. Journal of Diabetes Investigation 9: 713 – 725.