Should You Consider CGMs for Patients With Early Diabetes?

Emerging evidence and clinical experience suggest continuous glucose monitors (CGMs) may offer meaningful insights for patients with early type 2 diabetes or prediabetes, supporting behavior change and more personalized risk assessment.

“I am a strong advocate for the strategic use of CGMs in prediabetes,” said Mihail Zilbermint, MD, an associate professor of clinical medicine in the Division of Endocrinology, Diabetes, and Metabolism at Johns Hopkins University School of Medicine in Baltimore. “They have a great potential to transform how we engage patients who are at risk; they provide real-time feedback, making invisible things visible.”

Kevin Miller, DO, board-certified family physician and member of the American Diabetes Association’s Primary Care Committee, said CGMs are here to stay. “I don’t think there is any going back; we’re going to be using them.”

Yet, there are barriers to accessing CGMs. There is also a lack of long-term data and consensus among experts on their broader use.

The Case for CGMs in Early Diabetes

Available by prescription and over the counter, CGMs measure interstitial glucose levels via a small sensor placed under the skin. They enable trend analysis, time-in-range tracking, and identification of fluctuations in blood glucose levels.

These features help patients link diet, sleep, stress levels, and activity with glycemic variability, ultimately unveiling patterns — perhaps their most critical role, said Anne Peters, MD, director of the University of Southern California’s Clinical Diabetes Programs.

“I think CGMs are great because they make people aware of the composition of their food,” she said. If a patient starts to notice that eating cereal for breakfast increases their blood sugar level to 200 mg/dL, they may stop eating cereal for breakfast — and be healthier for it.

Data suggest as much. “Some emerging studies suggest that intermediate CGM use can improve food choices, physical activity, and overall glycemic variability, even in people without diabetes,” Zilbermint said.

One study published in Diabetes, Obesity and Metabolism found that CGMs paired with education led to weight loss and improved low-density lipoprotein cholesterol levels in people with type 2 diabetes and prediabetes. Other research has found that CGM use with personalized nutrition therapy doubled weight loss and fat reduction in people with prediabetes.

The Limitations of CGMs

Early studies and expert opinion suggest that CGMs may support behavior change and improve metabolic markers in people with prediabetes or early type 2 diabetes, yet data from long-term randomized controlled trials to support routine CGM use in these populations are lacking.

The American Diabetes Association and the Endocrine Society acknowledge the potential of CGMs in broader populations. Still, current guidelines do not recommend their routine use in those with prediabetes or type 2 diabetes who are not on insulin or other glucose-lowering agents.

Miller, currently involved in research on using CGMs in those with prediabetes and without diabetes with Abbott , said more research is necessary.

“We invented insulin 100 years ago; we’ve had fuel for the car, but we’ve had no speedometer, no way of gauging. I tease people that if a police officer pulled you over, you’d have no idea why. CGMs provide some of that data.”

CGMs, though, have cost and coverage barriers. Most insurance companies will not cover them unless a patient uses insulin, Peters said, and their cost over the counter can be prohibitive, which can be “very frustrating” in primary care settings.

“In an ideal world, we’d place continuous glucose monitors on individuals with a family history of diabetes or evidence of glucose intolerance,” Peters said.

But some of the very populations at highest risk for prediabetes and type 2 diabetes — Native American, Latino/Hispanic, Black, Asian American, and Native Hawaiian or Pacific Islander — often come from underserved communities with limited access, she said. When she provided CGMs to patients in her East Los Angeles clinic, outcomes improved.

“Just seeing their glucose patterns made a difference. Regardless of education or health literacy, when patients can recognize a spike and realize, for example, that two tortillas are better than four, it changes behavior.”

Clinics like Peters’ receive sample CGMs and use them intermittently with patients to support behavior change. Even short-term use — wearing a sensor for 2 weeks, then again 6 months later, for example — can help patients track changes even if they’re not used regularly, Peters said.

Of course, another area where physicians struggle regarding CGMs is that there’s no “standard” for what is normal, Peters said. A recent study Zilbermint was a part of evaluated how 18 expert clinicians interpreted CGM data in people without diabetes. More than half of the experts recommended follow-up for people who spent more than 2% of their time above the target range on a CGM, even when their A1c was below 5.7% and their fasting glucose level was < 100 mg/dL.

Yet, there was no consensus for recommending follow-up. Even experienced clinicians struggle to interpret CGM data in people without diagnosed diabetes, Zilbermint said.

“I think diabetes technology, including CGM, is one of the single best advancements for people with diabetes, but not every endocrinologist believes this,” he said. “Some of my colleagues have a more cautious approach, particularly in people without diabetes.”

One area of hesitation is around an overreliance on data. “We don’t want to measure to the point where it can backfire and add distress,” Miller said.

Where CGMs Fit in Primary Care

CGMs can be powerful tools for select patients, particularly those with type 2 diabetes on medications. They can also be helpful for those with prediabetes or early diabetes, providing awareness that can prompt lifestyle changes.

Guided data interpretation is essential. Miller said he’s seen TikTok influencers claim they’ll never eat strawberries again after seeing a glucose increase.

It’s also critical to consider CGM use within the broader context of a patient’s lifestyle and capacity, ensuring usage supports health goals without creating additional burdens.

Follow-up appointments initiated by the provider are key to meaningful progress, too. “I don’t want to be the inertia in someone’s progress,” Miller said.

While he emphasizes the need for greater systemic physician education around CGM use, he also encourages physicians less familiar with CGMs to empower interested patients to explore over-the-counter options and check back in with data for shared decision-making.