Can New Monitoring Technology Improve Your Diabetes Care?

By Felice A. Caldarella, MD, FACP, CDE, FACE
Man checking glucose monitoring app on cell phone

If you have been diagnosed with diabetes, would you like to know your blood sugar reading without having to do a finger stick? Would you like to receive automatic alerts if your blood sugar is dropping too quickly? Would you like to be able to share your blood sugar readings with friends and family? Would you like to be able to lower your A1C – a measure of the previous three months’ average blood sugar – without experiencing more frequent low blood sugar readings?

All of this is possible today with a continuous glucose monitoring (CGM) system. And depending on your insurance plan, the cost of a CGM might actually be covered by your policy.

A CGM is a device that continually tracks blood glucose (blood sugar) levels in the interstitial tissue fluid, the fluid that surrounds the cells of your tissue below your skin. The CGM contains a small sensor wire that is inserted under your skin, usually on your belly, to take blood glucose readings on set intervals. The wire is attached to a pad on the skin surface that acts as a receiver of information. A chemical reaction occurs on the wire in response to the fluid, which the receiver then sends wirelessly to either a monitor, smartphone display or tablet, allowing you to track your blood sugar average over the previous minutes without performing a finger stick. Sensors are changed every several days (timing depends on the device brand), which you can conveniently do yourself at home.

There are currently three FDA-approved CGM systems available in the U.S. They are the Dexcom CGM, the FreeStyle Libre and Medtronic Connect.

The beauty of CGM technology is that it allows you to see your glucose level any time at a glance and how your glucose changes are trending over a few hours or days. Accessing your glucose levels in real time and how they are trending can help you make more informed decisions throughout the day about how to balance your food, physical activity and medicines.

Some people think only those on insulin pumps benefit from a CGM system. This is not true. CGM systems have been shown to also benefit patients using multiple injections of insulin per day to manage their diabetes. So, if you require at least three injections a day – a combination of basal or long-acting insulin along with bolus or mealtime insulin – you could be a candidate for a CGM.

Research bears this out: In a recent trial, people with type 1 diabetes using injections of insulin wore a CGM system. Prior to wearing the CGM system, study participants were checking their blood sugar, on average, five times a day (many diabetes specialists often recommend four to six blood sugar checks a day). After 24 weeks, patients on the CGM system had better blood sugars on average and without increasing episodes of hypoglycemia (low blood sugar). This is an important finding given what we know about people with diabetes benefiting from lower, near non-diabetes-range blood sugars.

Plus, the A1c blood value (a measure of the previous three months’ average blood sugar) is a marker for the risk of developing diabetes complications such as eye, kidney and nerve damage. So, if you have type 1 diabetes, have been checking your blood sugar four to six times a day, and aren’t happy with your A1c value, perhaps a CGM system might be right for you.

Another reason to use a CGM system would be if you have hypoglycemia unawareness or severe hypoglycemia. Hypoglycemia unawareness is the loss of the ability to sense that blood sugar is dropping until the sugar is critically low. It typically occurs with people who have had diabetes for a long time and have frequent low blood sugars. This can be a very dangerous condition. Severe hypoglycemia is typically described as a person experiencing low blood sugar that requires assistance from another person to treat.

CGM benefits a user optimally when it is used continuously. Studies show that the improvement in blood sugar control wearing the CGM are lost when participants stopped wearing the CGM device. This is important to note if your insurance company decides to stop covering your CGM system because your diabetes went from uncontrolled to controlled on the CGM. In this circumstance, your doctor can advocate on your behalf with this information.

As with all technology, using a CGM takes some getting used to. One nice feature of CGM systems is that not only will they tell your current blood sugar reading, but also will let you know if your blood sugar is changing and in what direction. So, if you are going to eat and self-administer insulin but see that your blood sugar is 150 and dropping, you may give yourself less insulin. If instead your blood sugar is 150 and rising, you may decide to give yourself a little extra insulin with your meal. These adjustments can help fine-tune your diabetes management and might require a discussion or two with your diabetes clinical team as to what extra dosing (or less dosing) guidelines would be the best.

When you see your endocrinologist, be sure to bring your receiver to the office visit if you hadn’t already downloaded your device information to the Internet the night before the visit. The data helps your care team make the appropriate adjustments to your diabetes management program. Data can also be reviewed and analyzed between visits if you are having concerns with your diabetes control, but only when specific trends can be seen.

While CGM has proven its value to patients since its introduction in 2000, the device can be costly when not covered by insurance, especially for those who are older and on a limited income. Some good news on this front occurred in 2017, when the U.S Centers for Medicare and Medicaid Services (CMS) issued regulations allowing for coverage for CGM systems as “Durable Medical Equipment” under Medicare Part B, just like glucose meters. Until then, people with diabetes on CGM systems who aged into Medicare faced a tough decision, because the cost of the CGM systems were not covered. Medicare’s change in coverage meant patients who had benefitted from CGM would no longer be faced with this difficult decision.

There are, however a few specifics that must be met in order for a system to be eligible for Medicare coverage. First, it needs to be “therapeutic.” This means the blood sugar readings from the CGM system are accurate enough that a corresponding finger stick is not needed for the patient to act on the reading. There also has to be a non-disposable component to the CGM system which would last for three years – the receiver, for example. Two FDA-approved CGM systems meet this criteria: FreeStyle Libre and Dexcom CGM.

Also, in order for a Medicare patient with diabetes (either type 1 or 2) to receive coverage for a CGM system, he/she must be injecting insulin at least three times daily or using an insulin pump and checking their blood sugars by finger sticks at least four times a day, supporting the understanding that frequent adjustments in insulin dosing are being done based on blood sugar readings. Patients must also see their doctors every six months at minimum.

It’s hard to believe we’ve gone from testing a person’s urine in the doctor’s office to using technology advanced enough to predict if a blood sugar is going up or down, all without a finger stick. And CGM systems continue to improve rapidly. Measurement accuracy has more than doubled since the technology’s debut, device size and costs have been reduced, and patient and caregiver satisfaction with CGM therapy has increased. So, as you consider your diabetes care options, make sure to speak with your endocrinologist about whether a CGM should be in your diabetes toolbox.