A study published in the December issue of the journal Diabetes Care showed that using a continuous glucose monitor helped people with poorly controlled Type 1 diabetes lower their blood glucose levels.
A continuous glucose monitor is a device that consists of a sensor worn under the skin that transmits information about the body’s glucose levels to a receiver. The receiver, which is generally about the size of a pager, displays frequently updated glucose levels and stores information about changes in glucose levels over time. The device can also be programmed to set off alarms when glucose levels become too low or too high.
The study, called the GuardControl Trial, lasted three months and followed 156 adults and children with Type 1 diabetes in seven countries. All of the study participants used either an insulin pump or multiple daily injections to control their blood glucose levels, and all had HbA1c levels (a measure of blood glucose control over two to three months) of 8.1% or higher at the start of the trial.
The participants were divided into three groups: One group used a continuous glucose monitor continuously for three months, one group used it for three days every two weeks, and one group (the control group) did not use it at all. The people who were using continuous glucose monitors were instructed to confirm glucose levels with a fingerstick if the high or low glucose alarms went off and to take corrective action accordingly. People who were not using continuous glucose monitors were instructed to continue monitoring their blood glucose levels by fingerstick as usual.
By the end of the study, 50% of the people who wore a continuous glucose monitor continuously experienced at least a 1% drop in their HbA1c levels, compared to 37% of the people who used a continuous glucose monitor for three days every two weeks and 15% of people who did not use one at all. A greater proportion of the continuous glucose monitoring group also experienced at least a 2% drop in HbA1c levels—26%, compared to 9% of the three-day group and 4% of the control group. What’s more, significant reductions in HbA1c were seen in the continuous monitoring group as early as one month into the trial. A 1% drop in HbA1c level has been associated with a 35% reduction in diabetes complications as well as a significant reduction in health-care costs.
Further studies like this one should help define treatment guidelines for the use of continuous glucose monitors and pave the way for insurance coverage of the devices in the United States.
This study used the Guardian RT Continuous Glucose Monitoring System, which is manufactured by Medtronic MiniMed. Other continuous glucose monitors currently on the market are the STS Continuous Glucose Monitoring System from DexCom and the REAL-Time Continuous Glucose Monitoring system, also from Medtronic MiniMed, in which the receiver is combined with an insulin pump. Another continuous glucose monitor called the FreeStyle Navigator from Abbott Diabetes Care is currently awaiting approval from the U.S. Food and Drug Administration.
For a firsthand account of continuous glucose monitoring, check out “New Monitoring Technology Brings Movies Instead of Snapshots” by Jan Chait.