Some devices are being sold OTC for individuals without diabetes to track their health.
Continuos glucose monitoring (CGM) devices provide real-time updates of blood glucose by inserting a sensor beneath the skin that transmits data to a wireless handheld device, smartphone, or compatible insulin pump. Continuous readings equip physicians with a more complete understanding of a patient’s glycemic daily patterns.
Key information such as time in range and degree of variability can improve overall glycemic control, reduce hyper- and hypoglycemia, and improve quality of life. With the expanding role of CGM devices in diabetes management, knowing the available FDA-approved devices, key recommendations, associated costs, and general counseling will help ensure optimal outcomes.
AVAILABLE FDA-APPROVED CGMS
Table 11-6 lists available real-time CGM devices, which include a sensor, transmitter, and handheld receiver. Benefits include personalized audible alerts, continuous transmission, and data sharing with multiple devices or individuals. However, these devices can be challenging to set up, and patients without insurance coverage may find them costly.7
BEST CANDIDATES FOR CGM DEVICES
Proper education and training maximize CGM benefits. Prior to initiating CGM, patients and physicians should discuss insurance coverage, adherence, health care and technological literacy, and personal preferences. If patients or caregivers can operate CGM devices safely, American Diabetes Association (ADA) guidelines recommend offering CGM devices to8:
Furthermore, CGM may help patients with awareness of hypoglycemia. In general, CGM benefits patients who want more comprehensive information about their glucose trends.
ADA guidelines recommend patients read their real-time CGM data daily and check intermittently scanned CGM devices every 8 hours.8
ADVANTAGES AND DISADVANTAGES
Table 29 lists pros and cons of CGM use. Those unsure about trying CGM should consider some of its features when deciding.
Skin reactions such as irritation or hypersensitivity to the adhesive may occur. Patients should disinfect and dry the skin completely before inserting the sensor, alternating among 6 to 10 insertion sites. Liquid barriers or preps also can reduce skin irritation. However, persistent irritation may warrant referral to the patient’s primary care provider (PCP).10
Prescribers and pharmacists should review the patient’s active medication list before and periodically after initiating CGM. Medications such as hydroxyurea, acetaminophen, tetracyclines, aspirin, and mannitol can affect the device’s accuracy.8 Prescribing information supplies further recommendations.
Pharmacists and PCPs should counsel patients to plan ahead to refill prescriptions and supplies. Patients with constant access to sensors and transmitters at their pharmacy are more likely to avoid unnecessary monitoring interruptions.8
Historically, the Centers for Medicare & Medicaid Services covered FDA-approved CGM devices for patients with intensive insulin therapies. As of April 16, 2023, Medicare expanded its coverage to patients using any type or amount of insulin. It also covers patients with histories of problematic hypoglycemia.11
Private insurance coverage varies widely among plans and states. Eligibility requirements vary depending on patient age, diabetes type, frequency and intensity of insulin regimen, history of glycemic control, and more. Additionally, despite growing evidence of CGM’s benefits for patients with type diabetes, many insurers restrict coverage policies.12,13
Patients and providers should also consider indirect costs associated with different devices. For instance, not all devices are compatible with older smartphone models. The cost of added features or programs can quickly add to a CGM device’s total cost.
Nonprescription access to CGM gives individuals who don’t have diabetes greater insight into improving their diet and losing weight. Companies such as January AI, Levels, Nutrisense, Signos, and Veri offer CGM devices for sale online. Patients can purchase a device and monitoring plan, usually upon completion of a brief survey.14
However, OTC devices do not benefit everyone. For individuals who are still unsure, pharmacists can counsel them on the differences between devices. This also provides a chance to remind patients to eat balanced meals, obtain adequate sleep, manage stress, and visit their PCP regularly.
New CGM technology is on the horizon. Several companies are chasing the idea of a noninvasive glucose tracking watch. In 2018, PKVitality branded their K’Watch Glucose as a novel device that measured blood glucose through painless microneedles in the skin. In addition, rumors have resurfaced about Apple’s plans to develop a watch that uses light pulses to measure glucose levels.15 Other companies such as Dexcom continue to release improved versions of their existing technology that boast a more accurate and portable design.
CGM technology continues to rapidly expand to meet the growing popularity of blood glucose tracking.
1. Dexcom G6 CGM System. Dexcom. Accessed June 7, 2023. https://www.dexcom.com/en-us/g6-cgm-system
2. Dexcom G7 CGM System. Dexcom. Accessed June 7, 2023. https://www.dexcom.com/en-us/g7-cgm-system
3. FreeStyle Libre 2 features. Abbott FreeStyle Libre. Accessed June 7, 2023. https://www.freestyle.abbott/us-en/products/freestyle-libre-2.html
4. FreeStyle Libre 3 features. Abbott FreeStyle Libre. Accessed June 7, 2023. https://www.freestyle.abbott/us-en/products/freestyle-libre-3.html
5. Guardian Sensor 3. Medtronic. Updated February 2022. Accessed June 7, 2023. https://www.medtronic.com/us-en/healthcare-professionals/products/diabetes/continuous-glucose-monitoring-systems/guardian-sensor-3.html
6. Introducing the Eversense E3 CGM. Ascensia Diabetes. Accessed June 7, 2023. https://www.ascensiadiabetes.com/eversense/
7. Lee I, Probst D, Klonoff D, Sode K. Continuous glucose monitoring systems – current status and future perspectives of the flagship technologies in biosensor research. Biosens Bioelectron. 2021;181:113054. doi:10.1016/j.bios.2021.113054
8. Kahn SE, Anderson CAM, Buse JB, et al. (eds). American Diabetes Association Standards of Care in Diabetes – 2023. 2023;46(1). ISSN 0149-5992
9. Weighing CGM pros and cons. Danatech. Accessed June 7, 2023. https://www.diabeteseducator.org/danatech/glucose-monitoring/continuous-glucose-monitors-(cgm)/cgm-101/pros-cons-of-cgm
10. Messer LH, Berget C, Beatson C, Polsky S, Forlenza GP. Preserving skin integrity with chronic device use in diabetes. Diabetes Technol Ther. 2018;20(suppl 2):S254-S264. doi:10.1089/dia.2018.0080
11. Continuous glucose monitors. American Diabetes Association. Updated March 2023. Accessed June 7, 2023. https://diabetes.org/get-involved/advocacy/continuous-glucose-monitors
12. Kruger DF, Anderson JE. Continuous glucose monitoring (CGM) is a tool, not a reward: unjustified insurance coverage criteria limit access to CGM. Diabetes Technol Ther. 2021;23(suppl 3):S45-S55. doi:10.1089/dia.2021.0193
13. Oser TK, Litchman ML, Allen NA, et al. Personal continuous glucose monitoring use among adults with type 2 diabetes: clinical efficacy and economic impacts. Curr Diab Rep. 2021;21(11):49. doi:10.1007/s11892-021-01408-1
14. O’Connor A. Can technology help us eat better? The New York Times. Updated December 21, 2021. Accessed June 7, 2023. http://www.nytimes.com/2021/02/08/well/diet-glucose-monitor.html
15. Bajarin T. Why continuous glucose monitors are vital for diabetic health. Forbes. February 28, 2023. Accessed June 7, 2023. https://www.forbes.com/sites/timbajarin/2023/02/28/why-continuous-glucose-monitors-cgm-are-vital-for-diabetic-health/?sh=483ef4bb32b8