Department of Pharmaceutical Care, University of Iowa Hospitals & Clinics, Iowa City (Dr. Schleich); Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City (Drs. Schleich and Ray) kevin-schleich@uiowa.edu
The authors reported no potential conflict of interest relevant to this article.
Medicare Part B has established criteria by which patients with T2D qualify for a CGM (TABLE 332). A Medicare patient who has been determined to be eligible is responsible for 20% of the out-of-pocket expense of the CGM and supplies once their deductible is met. Once Medicare covers a CGM, the patient is no longer able to obtain fingerstick glucose supplies through Medicare; they must pay the cash price for any fingerstick supplies that are determined to be necessary.32
Once Medicare covers a continuous glucose monitor, the patient is no longer able to obtain fingerstick glucose supplies through Medicare.
Patients with private insurance can obtain CGM supplies through their preferred pharmacy when the order is written as a prescription (the same as for fingerstick glucometers). That is not the case for patients with Medicare because not all US distributors and pharmacies are contracted to bill Medicare Part B for CGM supplies. A list of distributors and eligible pharmacies can be found on each manufacturer’s website.
Risk–benefit analysis
CGMs are associated with few risks overall. The predominant adverse effect is contact dermatitis; the prevalence of CGM-associated contact dermatitis is difficult to quantify and differs from device to device.
FreeStyle Libre. In a retrospective review of records of patients with diabetes, researchers determined that a cutaneous adverse event occurred in approximately 5.5% of 1036 patients who utilized a FreeStyle Libre sensor.33 Of that percentage, 3.8% of dermatitis cases were determined to be allergic in nature and related to isobornyl acrylate (IBOA), a chemical constituent of the sensor’s adhesive that is not used in the FreeStyle Libre 2. Among patients who wore a sensor and developed allergic contact dermatitis, interventions such as a barrier film were of limited utility in alleviating or preventing further cutaneous eruption.33
Dexcom G6.The prevalence of Dexcom G6–associated allergic contact dermatitis is more difficult to ascertain (the IBOA adhesive was replaced in October 2019) but has been reported to be less common than with FreeStyle Libre,34 a finding that corroborates our anecdotal clinical experience. Although Dexcom sensors no longer contain IBOA, cases of allergic contact dermatitis are still reported.35 We propose that the lower incidence of cutaneous reactions associated with the Dexcom G6 sensor might be due to the absence of IBOA and shorter contact time with skin.
