CGM therapy for patients with T1D

If you're a healthcare provider who sees patients with diabetes, you already know that sore fingertips is one of their most common complaints. Yet for many patients, regular blood glucose monitoring is essential for keeping blood glucose and A1c in range. Patients with highly variable blood glucose levels may test five times a day or more, so it's no wonder they tire of pricking their fingers. Continuous glucose monitor (CGM) therapy may be the key to happier patients with better outcomes, especially for those with type 1 diabetes (t1d).

How does CGM therapy work?

A CGM consists of three basic components: A small sensor inserted under the skin, a receiver for data storage and display, and a transmitter that communicates between the two. Depending on the manufacturer of the CGM device, interstitial glucose levels may be measured automatically in 5-minute increments (as with the Dexcom) or on-demand when a patient activates the CGM by waving a receiver over the site of sensor insertion (as with the Freestyle Libre). Patients can then make adjustments to insulin injections and/or carbohydrates consumed in real time using recommendations from their clinical team.

Which patients are CGM candidates?

From a practical standpoint, the patients who will most benefit from CGM are those with hypoglycemia unawareness, nocturnal hypoglycemia, and needle phobia. However, any patient who uses multiple daily injections or an insulin pump is a candidate for CGM therapy. A 2020 study of 891 patients ages 18-30 found that CGM therapy reduced A1c by an average of 0.5 to 1.2 points. Study participants using sliding scale insulin schedules experienced the greatest decrease in A1c levels.

Currently, a Medicare beneficiary must be using an insulin pump or injecting insulin at least three times a day to qualify for CGM coverage. This means all Medicare recipients with type 1 diabetes and some Medicare recipients with type 2 diabetes will qualify for CGM therapy. CGM coverage for patients with private insurance varies according to individual policy.

CGM safety features

For those with hypoglycemia unawareness or nocturnal hypoglycemia, care should be taken to order a CGM that automatically checks glucose levels every five minutes, rather than one that requires the patient to participate in scanning their receiver over their CGM sensor manually. CGMs with automatic glucose checks can be set to alert patients to rapidly rising or falling blood glucose levels with audible or vibratory alarms, waking the patient before they become severely hypoglycemic.

Children with diabetes, vulnerable elderly patients, and people with diabetes who live alone may enjoy the added security of allowing a friend or family member to remotely monitor their glucose levels using an app installed on their cell phones. Remote monitoring allows friends and family to keep an eye on a person's blood glucose levels in an unobtrusive way so that the person with diabetes can feel as independent as possible.

Inside the clinic, software can download CGM data in a matter of minutes. This data can help providers and patients make better decisions about insulin adjustments, avoiding under- or over-insulinizing patients.

The future of CGM therapy

The first marketable continuous glucose monitor was introduced in 1999. Marketed by Minimed, the device required fingerstick calibration every 6 to 12 hours, and the sensor and receiver were connected with a wire. Today, CGMs are equipped with wireless technology and may be worn for as many as 14 days without fingerstick calibration.

The future development of the "artificial pancreas" is expected. This would mean longer-term integration of CGM devices and automated insulin dosing (AID) systems. Additionally, CGM sensors are expected to get smaller, thinner, and potentially less expensive.

As CGM technology evolves, many patients with t1d will continue to benefit from the flexibility CGM therapy provides.

Interested in learning more about living with diabetes and diabetes management? Visit the Edgepark Health Insights blog.