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Videos of health buffs sporting continuous glucose monitors (CGMs) have popped up all over social media, garnering millions of views with tutorials touting the devices' potential for weight loss and improved metabolic health.
But while these new claims have generated interest in CGMs outside of their indicated use, is there any evidence of benefit for people without diabetes?
'It Would Take a Very Motivated Person'
"What doctors need to convey to their patients is that there may not be a benefit, particularly if glucose metabolism is normal," Yael Harris, MD, an endocrinologist at Northwell Health in Great Neck, New York, told 鶹ý.
Glucose levels in people without diabetes typically remain within the normal range most of the day, she pointed out. For example, one study showed that individuals without diabetes placed on CGMs for up to 10 days 96% of the time.
"It would take a very motivated person to be making dietary changes based on a CGM when the vast amount of time they're in the normal range," said Harris.
CGMs are currently FDA approved only for use in patients with type 1 or type 2 diabetes, alerting users in real time when they approach or experience hyperglycemic or hypoglycemic events, but no clear benefits have been demonstrated for adults with prediabetes, Harris pointed out, let alone people with normal glucose metabolism.
"You have to hypothesize that the small, little changes that they're seeing with these glucose monitors are going to change behavior," she said. "And that I find even less convincing than the idea that this is going to make a difference in people with prediabetes."
Harris noted that while an individual with prediabetes could gain information from a CGM about how particular foods or exercise affect their blood sugar levels, there are no data showing that this information would lead to lower rates of diabetes development.
David Lam, MD, an endocrinologist at the Icahn School of Medicine at Mount Sinai in New York City, told 鶹ý that he's witnessed secondary benefits among his patients with diabetes with the near-real-time data CGMs can provide.
"They start to see their own glucose patterns," he said. "There is a better understanding of how their diet, activity, and medications impact their glucose levels. This can often lead to positive changes made by the patient."
And Lam said he's noticed an uptick in the number of patients with diabetes at his practice interested in CGMs, driven either by advertisement or word of mouth.
"I am generally supportive of this, because it reflects an interest and an increase in patient engagement with their healthcare," Lam explained. "I typically find that I still need to educate them on the nuances and limitations of the technology."
Limitations, Out-of-Pocket Costs
Lam and Harris both cited a learning curve in interpreting CGM results or grasping the devices' limitations, and Harris cautioned that CGM results come with an innate level of inaccuracy, especially in the low glucose range, which may lead to inappropriate actions.
"If someone does not have diabetes -- or even has prediabetes -- and is now getting signals from their CGM that their glucose is too low, that could drive them to now eat things that they otherwise wouldn't have eaten," Harris said, noting that the devices and settings are really designed for people with diabetes.
Cost is another factor to consider, as CGMs are usually not covered by insurance for people without diabetes.
"These are expensive devices, and it's almost a miracle if we can get them covered for people who are diabetic much less for anybody else," Caroline Apovian, MD, of Brigham and Women's Hospital in Boston and a past-president of the Obesity Society, previously told 鶹ý.
Despite recent improvements in coverage for people with diabetes, said Lam, high costs and insurance limits still remain barriers to use. "The medications themselves are often very expensive already, and this only adds to the grand total," he said.
For people paying out of pocket, start-up kits can run , depending on the brand. This accounts for the cost of the reader, transmitter, and replaceable sensors. Some digital health tech startups are even now specifically designing CGMs for people without diabetes in order to capitalize on this trend, advertising plans running around $200 per month for supplies.
Ultimately, Harris didn't close the door completely on prescribing a CGM to an interested patient without diabetes, so long as the individual is comprehensively informed.
"If a patient wanted to wear a CGM, particularly somebody who had prediabetes, and [they] understood that they would have to pay for it and understood that there's a level of inaccuracy, and what hypo- and hyperglycemia actually mean, I don't think it would be unreasonable to prescribe a CGM for that person," she said.