For CGM users, how often do you make insulin dosing decisions based solely on your CGM readings?
On Thursday, July 21, 2016, an FDA Advisory Panel voted 8-2 in favor of a non-adjunctive (replacement) insulin dosing label update for Dexcom's G5 CGM. This vote reflects what is happening in the real world: Dexcom CGM users are making decisions about their diabetes care based on their sensors readings (the number and the trend arrow). Based on our non-scientific poll, CWD readers are in fact using their CGM to make decisions -- 76% report always or sometimes dosing off their sensor reading.
One of the most compelling scientific arguments made at the panel meeting came from Boris Kovatchev, PhD, a pioneer in the mathematical modeling that underpins many of the artificial pancreas systems under development. During the open comment period, Dr. Kovatchev presented data from in-silico modeling (computer simulations), developed to test any CGM system, that showed a CGM system was safe to use to make insulin dosing decisions if its MARD (Mean Absolute Relative Difference, a measure of accuracy compared with a reference) was less than 10%. The Dexcom G5 system has an MARD of less than 10%, and thus it fits within the model developed by Dr. Kovatchev and his team.
There were many other compelling arguments, both scientific and emotional, and in the end the Advisory Panel voted overwhelmingly to approve the Dexcom G5 system for use in making insulin dosing decisions. Given that a large percentage of Dexcom users already dose based on their sensor, and the fact that this sensor serves as the foundation of many artificial pancreas systems, the panel's decision made sense.
In the years since, Dexcom has released an improved system, the G6, which does not require calibration.