The Advantages and Disadvantages of Continuous Blood Glucose Monitoring

Presented by Bruce Buckingham, MD (advantages) and Phillip Raskin, MD (disadvantages)
Session II – Artificial Pancreas
Friday, October 29, 2004

Reviewed by Joelle Escoffery, PhD

The use of technologies that allow for continuous glucose monitoring has a variety of advantages. They allow for real-time data analysis and the delivery of insulin based on that data. Continuous glucose monitoring devices can also be used for retrospective analysis. Patterns of hyperglycemia and hypoglycemia can be detected, and appropriate changes to the insulin regimen can be made. Such technologies can also provide alarms that alert patients when their blood glucose levels are outside of a predetermined range. This function is of particular value, as incidence of severe hypoglycemia has been estimated at 9%, with 75% of those episodes occurring at night. Further, in terms of detection of hypoglycemia, one study demonstrated that hypoglycemia (<65 mg/dL) was detected 136 times with a traditional meter, as compared with 311 times with a continuous monitoring device. When blood glucose levels <45 mg/dL were considered, the disparity was even more dramatic, with 5 episodes detected by a traditional meter compared with 319 episodes detected by a continuous monitoring device.

In terms of the potential disadvantages of continuous glucose monitoring, the issues of reliability and accuracy must be considered. The continuous monitoring devices are most accurate at values >100 mg/dL, and they tend to not function as well under conditions of rapid glucose excursions. Further, they are dependent on traditional monitors to calibrate. Finally, the cost of the continuous monitoring devices is high, making them an unrealistic option for most patients.

In conclusion, continuous glucose monitoring devices do have value as a supplement to, but not as a replacement for, traditional blood glucose monitors. They may have value for certain subgroups of patients (eg, patients with nocturnal hypoglycemia) and can provide value in a research setting. However, before these devices become widely used, further research assessing their impact on metabolic control needs to be conducted, and issues of accuracy, reliability, and cost need to be addressed.