T1D Exchange Glu Reaches 25,000 Members

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This is How The Glu Community Use CGMs

We take a look at data from several daily polls to see how people with type 1 diabetes use a CGM, why they choose to use a CGM, and why they don’t.

By Colleen Garey, Data Analyst Coordinator at T1D Exchange/GluColleenG

In the past year, several new continuous glucose monitors (CGM) have gained FDA approval and/or entered the U.S. market. Because of this, we thought it might be a good time to look back at several daily poll questions we asked the Glu community about CGM use.

Current Glu completed-profile data indicates that 55 percent of the community currently use a CGM. This is a much larger proportion of CGM use than has been reported of the type 1 diabetes community as a whole. 

When CGMs were first introduced, there was an average measurement error of more than 20 percent, meaning that one’s glucose levels  could have been significantly lower or higher than the CGM reading. In 2012 the measurement error decreased to around 13 percent. Companies have been working to shrink that percentage of variability with each new model; the Dexcom G6 touts a measurement error of under 9 percent. There is still work to be done, however, as Glu users often cite inaccuracy as their greatest concern to CGM use; currently, 43 percent of Glu users report inaccuracy as their greatest concern.

All but the newest CGM models require calibration twice a day with a fingerstick reading. But because of accuracy concerns, many CGM users in the past have opted to calibrate more often than recommended. In 2014, 71 percent of Glu users reported that they calibrated their sensor three or more times a day. This percentage decreased by 38 percent when the question was asked again in January 2018, with half of Glu users responding that they just calibrate their CGM the recommended two times per day.

Despite concerns about inaccuracy, about 40 percent of the Glu community in 2016 reported that they correct highs reported by a CGM without verifying that reading with a glucose meter always or most of the time. This was an increase from 2013 when only 21 percent reported that they regularly administer insulin to deal with a high reading without verifying with a fingerstick. Days after this question was posted, the FDA announced that the Dexcom G5 system was approved for non-adjunctive use, meaning that G5 users didn’t need a fingerstick to verify the reading before dosing. Eight months after the decision, over half of Glu users reported that they corrected high blood sugars based solely on the reading on their CGM most or all of the time.

Click on the graph to see a full-size version of the data. 

The most notable barrier to CGM adoption is cost. In 2016, over 60 percent of Glu users reported that out-of-pocket cost or lack of insurance coverage were the main reasons they do not currently use a CGM. In a similar survey in 2017, the percentage of Glu users reporting these concerns increased to over 70 percent.


It’s likely that the percentage of CGM use, and the perceptions surrounding CGM use will shift as the technology continues to improve. We will continue to do periodic Question of the Day surveys to see if new technology moves the needle of CGM use among our community.

To join Glu and take part, click here: https://myglu.org/sign_up.  


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