CGM "Debate" Finds Benefits, Barriers to Uptake for Type 2 Diabetes

Mary Caffrey

The mood was light—where else do the presenters’ slides feature the back side of a rhinoceros and a smiling monkey? But the message was serious: decades of trying and more than 40 drugs for type 2 diabetes (T2D) still leave large numbers of patients with poor glycemic control.

Is continuous glucose monitoring (CGM) the answer in T2D? For the right patients, yes—the challenge is identifying those patients, according to Jeremy Pettus, MD, and William H. Polonsky, PhD, CDE, both from the University of California at San Diego, the host city for the 77th Scientific Sessions of the American Diabetes Association, taking place June 9-13, 2017.

Sunday’s session, “Should Continuous Glucose Monitoring Be Prescribed for People with Type 2 Diabetes? A Pro/Con Discussion,” was styled as a debate, but Pettus and Polonsky turned it into a lively exchange of evidence that supports CGM use for patients with T2D, along with research gaps and practical barriers to bringing the technology to more patients.

They started with a key ground rule: they had refused to debate CGM use for patients with type 1 diabetes (T1D), because it’s the standard of care. And they took note of the very recent Medicare rule change that may soon bring Dexcom’s G5 to beneficiaries who have type 1 or some patients with type 2, although some administrative hurdles remain.

After Polonsky took the “con” position for sections on patients who use insulin, he and Pettus switched sides—and suit jackets—to debate CGM use for those using oral medication, who represent most people with diabetes.

Pettus started with an update from the DIAMOND study, which previously found that CGM was just as effective for T1D patients using multiple daily injections of insulin as those using pump therapy. New data from both T1D and T2D users shows CGM helps those using daily injections across both patient groups.  

The question about CGM, Pettus said, “Is it worth the burden and the cost?” It’s worth noting, he said, that patients associate how sick they are with the number of medications they take, and unlike medication, CGM has “no side effects.”

There are concerns about patients learning to use CGM, especially if they develop T2D when they are older and less tech savvy. But Pettus said there’s other evidence that shows with limited instruction—a one-page handout—patients with T2D learned to use CGM and that it made a difference. What’s more, he said, it made the biggest difference in patients with glycated hemoglobin (A1C) above 9%, a group that “we might write off as hopeless.”

For these patients, seeing what certain foods and exercise does to blood sugar proves an eye-opener. “People seeing it in real time is empowering,” Pettus said. Many assume CGM will require more of a doctor’s time, but in the long run it could require less.

“We have a paternalistic view of medicine, and that’s just not the case with CGM,” Pettus said. Armed with better tools, patients “might not need us, and that’s OK.”

Polonsky said the main challenge is that T2D patients with the most severe hypoglycemia haven’t been studied—and they should be. He also read from one of Pettus’ papers to raise the question whether patients had the confidence to actually use their CGM consistently. “Maybe,” Polonsky said, “but we need more evidence.”

Pettus sought to dispel several myths about CGM and basal insulin: (1) titration with self-monitoring isn’t perfect; (2) people will use the results, as seen in one study that showed patients using CGM ate fewer calories, lost weight, and exercised more; (3) hypoglycemia is a significant problem in T2D, and tests with CGM showed people had events that might have gone unnoticed, but the CGM allowed them to act.

In response, Polonsky said a 2014 study involving CGM in T2D patients on basal insulin produced great results—but also involved frequent contact with the patients. There were 10 visits over 6 months, more than would happen in the real world. “Was it the CGM, or the remarkable support these folks got?” he asked.

When Pettus and Polonsky switched sides to discuss CGM use for those on oral agents, Polonsky—who is an advocate of advancing CGM in the right populations—presented data to show the dismal data on T2D, despite the ever-increasing number of medication choices.

“Why is it that so many folks have a tough time taking medications?” he asked. “Nobody is unmotivated to want to live a long life—we are at best ambivalent.”

“We know there are active fears about medication,” Polonsky said. By contrast, CGM can offer a chance “to become engaged and stay engaged.” The use of feedback, he said, “is the most underutilized tool we have.”

For some patients, CGM doesn’t have to be all the time or forever. Polonsky envisions that some T2D patients could “rent” CGM for a month, then maybe a few weeks a year, to get in touch with the patterns of their behavior and the effect on glycemic control.

Polonsky knows there’s an argument that patients will never understand the data. That’s the wrong question, he said. “What if we provided help and support so they know what these numbers mean?”

“Can we help people have this ‘Aha!’ experience?” he asked.

He read a case study of a T2D patient who started using CGM and now couldn’t imagine going back to “being blind” managing his diabetes without it. “The government might not think I need this,” the person wrote, referencing Medicare’s old policy, “but you’ll have to pry it from my cold, dead hands.”

Pettus ended with a photo of a crowded waiting room, likely in a primary physician’s office. The practical reality, he said, is that time constraints and insurance barriers make it too easy to just write a prescription than to take time to teach patients how to use CGM.

Pettus and Polonsky agree that CGM should only be tried in patients who show some willingness—the question is how to identify who they are, and they agreed more evidence is needed. CGM costs would need to come down, and the technology would have to become even easier to use. Insurance coverage will remain a barrier until there’s more evidence that the technology is cost-effective.

But Polonsky said the idea that patients with T2D might not use CGM because doctors are too busy, “makes me very sad.” 
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