CGM Use in T1D: Don't Count Older Patients Out

Richard Pratley, MD;  Mark Harmel, MPH


July 09, 2020

This transcript has been edited for clarity.

Older individuals with type 1 diabetes are at particular risk for hypoglycemia. This can be very serious. The consequences of hypoglycemia in older individuals include things like falls, fractures, cognitive impairment, and cardiovascular events. What can we do about this problem in older individuals with type 1 diabetes?

This was the topic of a paper we published in JAMA [in June], entitled "Effect of Continuous Glucose Monitoring on Hypoglycemia in Older Adults With Type 1 Diabetes." This was a randomized clinical trial conducted by members of the T1D Exchange and supported by the Helmsley Foundation and JDRF (formerly known as the Juvenile Diabetes Research Foundation).

In this study, we randomized 203 individuals above the age of 60 years with type 1 diabetes to either continuous glucose monitoring (CGM) using a Dexcom G5 or standard blood-glucose monitoring. The group that received standard blood-glucose monitoring had a blinded CGM placed at intervals throughout the 6-month period to assess hypoglycemia.

Marked Improvements in Time in Range

What did we find? The group that used CGM to manage their diabetes had a significant reduction in hypoglycemia, defined either as a blood glucose < 70 mg/dL or < 54 mg/dL on CGM. This amounted to a reduction of 30 minutes per day in time spent in hypoglycemia. It also translated to a 90% reduction in serious hypoglycemic events, which were defined as loss of consciousness, seizure, or the need for medical management.

This improvement in hypoglycemia did not come with a result of hyperglycemia. In fact, time within range was markedly improved in this study. There was also a reduction in time spent in hyperglycemia, defined either as blood glucose > 180 mg/dL or > 250 mg/dL.

We also observed that there was a high degree of utilization of CGM in this patient population. By the end of the trial, around 90% of the participants randomized to CGM continued on the CGM, and most were using it to dose their insulin.

What we've shown in this study is that CGM can markedly improve outcomes in older individuals with type 1 diabetes, it reduces serious adverse events, and it's well accepted by this patient population.

Breaking Down Barriers to CGM Use

Where does this take us? When we started this study, CGM was not reimbursed by Medicare. Now that we have the evidence, CGM is being reimbursed by Medicare. I think there are still barriers to CGM use in older individuals with type 1 diabetes. Those barriers are largely related to the perception that older individuals can't adapt to new technology.

But we've proven that wrong in this study. We've shown that older individuals can use the technology effectively to improve outcomes and reduce hypoglycemia. I encourage CGM to be used in all of our older patients with type 1 diabetes as a standard of care.

Where are we going in the future? The new devices, such as the Dexcom G6, are even easier to use and will overcome many of the barriers that patients might have to starting CGM. We also need to conduct trials with advanced insulin delivery technologies. Predictive low-glucose insulin suspend systems and hybrid closed-loop systems need to be tested in older individuals because of their high risk for hypoglycemia. I predict that they will be very effective in this population.

Stay tuned. We'll have more information in later years.

Thanks very much for your attention.

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