An FDA advisory committee panel recently determined that measurements from continuous glucose monitors (CGM) are safe and reliable enough to be used to make decisions for insulin dosing. Currently, the FDA advises people with diabetes to use fingersticks to determine how much insulin they should take. This recommendation could open up CGM coverage for many people on Medicare, and allow them to determine their proper insulin doses based on longer-term trends, rather than snapshots of data.
This change could result in a cost-saving measures for people with diabetes, since the frequency of blood glucose monitoring would be reduced to twice per day, says Lori Laffel, M.D., MPH, Chief of the Pediatric, Adolescent and Young Adult Section and Senior Investigator and Co-Head of the Section on Clinical, Behavioral and Outcomes Research at Joslin Diabetes Center.
This decision was reached based on a review of a number of clinical studies involving the Dexcom G5 CGM, including research conducted at Joslin. There was also a public discussion on this subject before the final recommendation, at which Dr. Laffel testified in favor of the change along with two Joslin 50-Year Medalists.
“It was extraordinarily compelling to hear public testimony from patients, family members, health care professionals, and professional societies who were nearly all overwhelmingly in favor of the proposed label change to allow use of the Dexcom G5 CGM device in non-adjunctive manner,” she said.
Should this recommendation be officially adopted by the FDA (which is likely), it could allow CMS/Medicare to provide coverage to thousands of recipients for these devices. Hypoglycemia unawareness and severe hypoglycemia, or extreme low blood sugar, can cause significant problems for people with type 1 diabetes, and constant monitoring with the CGM could improve management in those people.
To reap these benefits, it’s necessary to maintain strict calibration of the CGM according to the manufacturer’s label.
When used properly, CGMs are as safe as fingersticks. “The CGM requires calibration twice daily. To safely use the CGM device, it is critical to ensure that there is a glucose value along with a trend arrow; both help to ensure that the CGM is functioning properly and can likely be used as a replacement for fingersticks glucose determinations,” she said.
Risks crop up when the device isn’t calibrated correctly, when the user can’t view the glucose value or the trend arrow on the screen, or when someone with diabetes might ignore the symptoms of high or low blood glucose because the CGM reports a normal glucose levels. (If someone with diabetes feels either high or low but the device is reporting normally, [s]he should still confirm the reading with a fingerstick.)
Overall, the benefits of using CGM as the primary form of glucose monitoring outweigh the risks. “CGM provides important glucose information throughout the day and night, at times when fingersticks are unlikely to be checked,” says Dr. Laffel. “CGM benefits arise from use of the trend data, which allows patients to see the direction that the glucose is heading – it can be rising, falling, or staying the same. The trend allows for more careful insulin dosing.” Watching these trends can also let people with diabetes and their care teams understand how diet, exercise, stress, illness, and more affect individual blood glucose readings.
It’s important to note that the recommendation currently only applies to the Dexcom G5, since this was the device used in the studies on which the recommendations are based.
“The Joslin Clinic currently advocates and teaches use of many advanced diabetes technologies.” She said. “The proposed change in labeling for the Dexcom G5 device will allow Joslin educators and clinicians to provide proper education to patients and families on how to use CGM data to make diabetes treatment decisions.”
Please note, this post is not meant to be a review or an endorsement of any product mentioned.