'Better Glycemic Control Than I've Ever Seen'

Anne L. Peters, MD


October 25, 2019

This transcript has been edited for clarity.

Recently, I noticed something strange happening in my clinic. Most of my patients with type 1 diabetes are coming in with A1c levels below 7%—not slightly below 7%, but 5.7% to 6.5%. Many of these patients had had higher A1c levels for years and really struggled to bring them down.

When I think about it, there are two fundamental changes in the management of my patients with type 1 diabetes. Part of this is driven first by new concepts, specifically that of the ambulatory glucose profile, and second by new technology.

Time in Range

First, I'm going to talk about the concept that comes from patients wearing continuous glucose monitors, and that's the notion of time in range. An A1c result is a 3-month average, and it's kind of abstract. You can't tell based on an A1c of 7.5% whether a patient is high overnight and low in the afternoon. You only know what the average is.

The time in range tells you how much of the time a patient is in the range between 70 and 180 mg/dL. You know that a patient can have a good A1c of 6.5%, but be up and down and up and down. That's someone who may not feel like their diabetes is well controlled, and they may be suffering from frequent episodes of high and low blood sugars.

If somebody is oscillating with less variability within the range of 70 to 180 mg/dL, that person is really feeling better and seems to be under better control. It's hard to quantitate, but when I ask my patients, they feel as though their diabetes is well managed.

You can find this information on something called the "ambulatory glucose profile." Many of the sensor companies are providing this information to you. At the very least, they give you a number—the percent time in range. You want to look at how much of the time your patient is in range, and the goal is to get patients above 70%.

In addition, the ambulatory glucose profile can show you how much time the patient spent low (< 70 mg/dL or < 54 mg/dL) or high. I look at how much time a patient is spending low, because the first thing I generally want to do is help a patient avoid episodes of hypoglycemia.

Then, I work on the time the patient spent high. In general, we look at 2 weeks' worth of data. Retrospectively, over the past 2 weeks, how much time has the patient been in range? Again, I want patients to be 70% or more in range.

My patients can see this on their devices, look at their own scores, and tell me with pride that they are 80% time in range or even 90% time in range. It gives them a sense of success, as well as real data and metrics—time of day, profiles, and variability—that they need to improve their glycemic control.

Do-It-Yourself Systems

Many of my patients are also using do-it-yourself insulin delivery systems, which are really changing how they give insulin and how they manage their diabetes.

Years ago, a number of smart people got together and said, "We are not waiting. We have the technology and tools to create a hybrid closed-loop system, and we don't need to make any manufacturer do this—we can do it ourselves."

There are a number of these systems now that are not approved by the US Food and Drug Administration. They may be in the future, which would be nice. There is a whole group of patient-driven, automated insulin delivery systems that we can learn about. From my perspective, I want to make sure that my patients are safe using the systems. We can't prescribe them, but we can help patients use them safely.

These systems have three basic components. There is a communication link that the patient has to purchase; the control algorithm, which is the brains for the whole system; and a pump. Recently, the older Omnipod (Glooko)—not the Omnipod DASH—has been included in one of these systems.

Patients also need a continuous glucose monitor. The system links these pieces together and starts providing automated insulin delivery. A patient still has to give their bolus doses, but it manages to control the overnight basal values in a way that patients really like. What I've seen as more and more of my patients are using these systems is that their control gets better and better.

The plus side of these systems is that they're infinitely adjustable. I can work with a patient who wants to target a glucose level of 100 mg/dL and help them to safely reach their target and stay there. Some of the commercial systems are slave to somewhat of a higher target, but in these systems, people can adjust them to suit their needs.

The downside is that they're not FDA regulated; they don't come with a manual; and for people who want to use them, it requires they do a lot of work to both set up the system and to maintain their control and safe standards in terms of their diabetes management.

Because I've spent so many years managing patients with technology who have type 1 diabetes, I can look at printouts from these devices, even if it's from somebody's smartphone, and understand the insulin delivery and how the device and program are making adjustments and changes. Having done this now for a number of years, I feel comfortable that I can help my patients.

Keeping Patients Safe

I also try to keep up with what my patients are learning through Facebook groups and websites—the same places from which our patients are getting their information.

I encourage you to understand what's happening so you can keep your patients safe. You shouldn't necessarily recommend these and you can't prescribe them, but you can prescribe the pieces and then support your patients to safely use these devices.

The combination of these hybrid closed-loop systems, whether it's the do-it-yourself, patient-driven models or the commercially available models—one from Medtronic or Tandem's Basal-IQ, which will hopefully soon be the Control-IQ—together with our patients who are knowledgeable and capable, are resulting in better glycemic control than I've ever seen.

It does, of course, require an educated, adherent patient, and I think that's really key. The tools are now there for the right patient. This isn't one size fits all. I know there are still many patients who aren't yet ready for this, but I do think continuous glucose monitoring is a tool that many patients can benefit from.

If you take that and start using the concept of time in range and looking to develop tools to help patients keep their glucose levels in range, we can help our patients better manage their type 1 diabetes.

Anne L. Peters, MD, is a professor of medicine at the University of Southern California (USC) Keck School of Medicine and director of the USC clinical diabetes programs. She has published more than 200 articles, reviews, and abstracts and three books on diabetes, and has been an investigator for more than 40 research studies. She has spoken internationally at over 400 programs and serves on many committees of several professional organizations.

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