Role of Continuous Glucose Monitoring (CGM) in Diabetes Management

Diana Isaacs, PharmD, BCPS, BCACP, BC-ADM, CDCES: Hello, and thank you for joining this Endocrinology Network® Patient Care® presentation titled “The Role of Continuous Glucose Monitoring in Diabetes Management.” We’re going to focus on the various factors that shape the use and impact of CGMs [continuous glucose monitors] in the treatment of diabetes. Let’s begin.

There are many challenges to the self-monitoring of blood glucose. One day, it’s going to be archaic, like how people used to have to test their urine for glucose. We couldn’t imagine that people would be peeing in a cup now and using that to test their glucose. Self-monitoring of blood glucose requires blood, which isn’t always fun. You have to use a lancing device, which is sharp and can feel painful. You have to draw a drop of blood. You have to carry supplies: test strips, a glucose meter, and a lancing device. It’s pretty inconvenient. It can feel painful.

It provides only 1 number at 1 point in time, so you don’t know the direction that the glucose is going. You could get a reading of 110 mg/dL, and someone could feel confident that their glucose is in the target range, but what if it’s dropping quickly? Unfortunately, that’s something that a blood glucose monitor isn’t able to tell somebody. However, a continuous glucose monitor can provide information about what the number is at that time along with the direction that it’s going in and also predict impending high or low glucose values.

CGM has many benefits and can improve disease management in both type 1 and type 2 diabetes. One thing CGM does very well is provide instant feedback on lifestyle choices. Someone could eat a cup of oatmeal and immediately see how that impacts their glucose value. I frequently have patients who tell me, “I noticed that when I eat oatmeal, it spikes a lot. I thought oatmeal was healthy compared with eggs. Eggs don’t raise me up very much.” Things like that are very helpful, along with the instant feedback about the benefits of exercise, such as walking after a meal.

There’s also the safety component. A lot of people are scared about going low—rightfully so. It’s very common that people might eat an extra bedtime snack because they’re worried about dipping low overnight. A CGM through that low alert can alert someone, so they can have the confidence that it’s OK for them to go to bed with their glucose in the target range. If it drops, they’ll get alerted and will be able to take action on that.

In terms of the health care team, the data are invaluable. If all you have is an A1C [glycated hemoglobin] reading and a few fingerstick readings, it’s like flying blind. You don’t know exactly what to do to the treatment regimen. If A1C is above target, you know you need to adjust something, but you don’t know if the person is having lows. With a CGM, you have all this information. You can determine exactly when someone isn’t in target range and then have more targeted intervention to help them increase time in range and obtain their A1C target.

There are a lot of data that show the benefits of a CGM, in terms of improving glycemic management. We have a number of randomized controlled trials with a real-time CGM, thinking back to the old DIAMOND trials in type 1 and type 2 diabetes. We also have a number of randomized control trials with intermittently scanned CGM. I’m not going to go through all the data, but the bottom line is that these trials showed that there were decreases in A1C as well as increases in that time in target range.

Time in range is becoming an important metric. That’s the time spent between 70 and 180 mg/dL. The reason this is becoming so important is because we know we can bring down A1C. A1C is an average, so we can bring it down by causing tons of hypoglycemia. Obviously, that isn’t good clinical management and won’t lead to good clinical outcomes. By increasing time in range, we can still achieve the A1C target, but in general we’re going to have safer outcomes, and people are going to feel better because they’re not going to be on this roller coaster of high and low or having tons of lows.

Other important things we’ve seen from the clinical trial data are improvements in quality of life and less diabetes distress, which is so important. There have been a number of cost-benefit analyses showing that through the use of CGMs and improvements in quality of life, as well as other important end points—like reducing hospital admissions for severe hyperglycemia and reducing emergency department admissions for hypoglycemia or hyperglycemia—there’s a huge cost benefit to using these devices. There are lots of great clinical data supporting the use of CGMs in people with type 1 and type 2 diabetes.

When we think about the burden on health care professionals, we know that people are being asked to see more patients. It can be challenging to take care of people with diabetes, especially if you have a 20-minute slot with their visit. CGMs have helped people reach their A1C targets and other metrics. The reduction in hospital and emergency department admissions is important and reduces the burden for health care professionals.

I want to add that a CGM could increase the burden if it isn’t implemented in a systematic way. That’s not a great thing to say. I’m a big advocate of the use of CGMs, but the reality is that you’re going to get more data, so your team has to have a process of who will look at the data, how you’re going to download the data, and what you’re going to do with it. Sometimes that involves a bit of training up front for the team, or at least figuring out who on your team is going to be the technology champion. That way you can implement good practices so that it doesn’t feel like an extra burden and is helping your practice provide the best care for your patients.

Transcript Edited for Clarity