FDA Okays Use of Dexcom G5 CGM for Insulin Dosing

Miriam E Tucker


December 20, 2016

For the first time, the US Food and Drug Administration has approved the use of a continuous glucose monitoring (CGM) system to replace finger-stick testing for determining insulin doses.

The decision officially expands the indication for Dexcom's G5 Mobile Continuous Glucose Monitoring System, previously approved only as an adjunct to finger-stick testing, for diabetes treatment decisions in patients 2 years of age and older with diabetes.

The move follows the advice of FDA's clinical chemistry and clinical toxicology advisory panel, which voted 8 to 2 in favor of the indication at a July 21 hearing.

Patients will still need to perform twice-daily finger-stick blood testing for calibration, but they will be able to base their insulin-dose calculations directly from the values displayed on the device's receiver or smartphone app.

Evidence supporting the indication came from two 1-week studies including 130 adults and children aged 2 years and older in which the system readings were compared with both glucose meter values and a laboratory reference. No serious adverse events were reported.

Potential risks associated with this use of the device include hypoglycemia or hyperglycemia in cases where the device is inaccurate or incorrect use of the hardware. For example, patients will often push sensor use beyond the 7-day approved period, and efficacy in those circumstances has not been reported.

In addition, use of acetaminophen-containing medications can lead to falsely elevated readings.

At the advisory panel meeting, there was discussion about how patients would be taught to incorporate the device's trend information into dosing calculations and who would be doing that teaching — the endocrinologist, the company, or allied health professionals.

The point was also made that many patients have been using the device for dosing already, and at least now Dexcom's customer assistance representatives will be allowed to advise them about it, which they had previously been forbidden to do.

The FDA move also possibly could influence Medicare's current non-coverage for CGMs, since the rationale had been based in part on the fact that the devices were merely "adjunctive."

For more diabetes and endocrinology news, follow us on Twitter and on Facebook.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.