The launch of the first over-the-counter glucose sensors last year has raised a debate about who benefits from these devices. The Food and Drug Administration cleared devices made by Dexcom and Abbott last year with a broad indication, allowing anyone who does not take insulin to use them.
During a session at the American Diabetes Association’s Scientific Sessions in June, a pharmacist and a physician debated the benefits and risks of these new devices. They both supported making CGMs more accessible to people with diabetes, but disputed the usefulness of the devices for adults without diabetes.
Diana Isaacs, a pharmacist and director of education and training in diabetes tech at the Cleveland Clinic, argued in favor of over-the-counter CGMs, saying they could be helpful for people who don’t have insurance coverage or who might have a hard time getting into a specialist for a prescription. David Ahn, an endocrinologist and chief of diabetes services at Hoag Hospital’s Mary and Dick Allen Diabetes Center, agreed that having glucose monitors easily accessible is “really exciting,” but raised concerns that patients might misinterpret the data and that the devices are not designed for accuracy in a narrower glucose range.
The ADA debate was part of a broader discussion that is happening after HHS Secretary Robert F. Kennedy Jr. touted CGMs at a recent congressional hearing, saying he would like all Americans to be wearing a health wearable within four years.
The difference between OTC and prescription CGMs
Currently, two over-the-counter CGMs are on the market: Dexcom’s Stelo device, which is marketed to people with Type 2 diabetes who don’t take insulin, and Abbott’s Lingo, which is tailored to the wellness market. Abbott received FDA clearance for another over-the-counter device, called Libre Rio, which is intended for people with Type 2 diabetes, but the company has not yet shared a timeframe for launch.
One key difference between over-the-counter and prescription CGMs is that the over-the-counter versions don’t provide hypoglycemia alerts. They also display a narrower range of glucose values. Dexcom’s G7 has a reportable glucose range of 40 to 400 milligrams per deciliter, while its Stelo app only displays ranges of 70 to 250 mg/dL. Dexcom’s Stelo also provides glucose readings every 15 minutes, while its G7 sensor provides them every five minutes.
Abbott’s Lingo similarly provides a range of 50 to 200 mg/dL, while its Libre Rio is expected to have a measurement range in line with prescription CGMs.
The over-the-counter devices focus on measuring glucose spikes, with Stelo issuing a “spike alert” while Lingo issues “points” for increases in glucose throughout the day.
Challenges with interpreting CGM data
One challenge for people without diabetes who may use a CGM is that glucose spikes are not well defined, Ahn said. For example, how do you distinguish if the “spike” is just a response to stress versus from having a high-carb meal?
It also raises the question of what the goal is for patients.
“Is our ultimate goal to not have any spikes at all and to have a flat line as a blood sugar?” he said. “Surely that’s not the case.”
While there are strong guidelines for time in range for people with diabetes, he added, there is no consensus statement or guideline for what “normal” is for people without diabetes.
Ahn also said CGMs are better at detecting high and low blood sugar levels, and may be less accurate in a tighter range. He wore both Dexcom’s Stelo and Abbott’s Libre 2 Plus for 13 days, and had an average glucose reading of 113 mg/dL from Stelo but an average of 85 mg/dL from Libre 2 Plus.
“Glucose spikes and misinterpreting data can lead to confusion, anxiety, and worse, disordered eating,” he said.
The argument for OTC devices
Isaacs looked to the history of diabetes devices to build an argument for over-the-counter CGMs.
At one point, finger sticks used to measure blood glucose were only available in doctors’ offices. Now, they can be bought without a prescription. When the first CGMs came to market, they were only accessible for people who had the privilege of being able to afford them and get a prescription, Isaacs said.
“I remember very vividly, in the earlier days of CGM, we had patients with Type 1 diabetes where some healthcare providers said, ‘Oh, I think that person is going to get too anxious seeing their numbers all of the time,’” Isaacs said. “Let the person decide.”
CGMs are much more accessible today. But for people without insurance coverage or a prescription, an over-the-counter CGM would often be cheaper than paying for a prescription device with cash, Isaacs said.
One area of potential benefit is for people with prediabetes, which accounted for roughly 38% of U.S. adults in 2021, according to the Centers for Disease Control and Prevention. Many people don’t know they are living with this condition, Isaacs said. Even though CGMs are not intended to diagnose diabetes, the results could prompt a person to see their physician and get testing, she said.
Isaacs also sees the devices as helpful for people with gestational diabetes, because many of those patients don’t take insulin, which can make it harder to get insurance coverage for a CGM.
For people without diabetes, Isaacs still sees CGMs as having a role in educating people about what foods and other lifestyle factors can lead to glucose excursions.
“What I would argue is that the benefit, for sure, outweighs the risk,” Isaacs said.
