An Advance in Blood Glucose Tracking for Prediabetes: Continuous Glucose Monitors

The First Over-the-Counter Continuous Glucose Monitor Becomes Available

The first over-the-counter continuous glucose monitor (CGM) received US FDA marketing clearance on 26 August 2024 for people over 18 who do not use insulin and are not at risk of hypoglycemia.

This development is not FDA approval, but FDA marketing clearance (cleared). This type of clearance is given when a device’s safety and effectiveness are confirmed, but it does not mean approval. Approval generally applies to higher-risk devices or drugs and is more comprehensively supported by clinical studies.

Dexcom’s device, called Stelo, was designed particularly for people with type 2 diabetes who do not use insulin or people with prediabetes (before diabetes develops).

It is now available over the counter in the United States for 99 dollars a month, or 89 dollars a month by subscription. However, it is not currently covered by insurance, and no financial assistance programs are available.

Like existing CGMs used by people with diabetes who take insulin, this waterproof device is worn on the back of the upper arm and transmits glucose levels to a smartphone in real time. Fingerstick blood sampling is not required; each sensor can be used for 15 days. Unlike existing CGMs, however, Stelo does not issue low-glucose alerts.

Studies show that people who track glucose with continuous glucose monitors achieve better glucose control, lower HbA1c levels, and improved quality of life with diabetes.

Before prescribing what patients know as weight-loss injections — GLP-1 (glucagon-like peptide 1) receptor agonists — physicians may ask patients to use CGMs so they can see the effects of the types and amounts of food they eat. These data may help people adjust dietary habits and behavior more effectively and be more successful in discontinuing medication.

In regions that have not yet adopted this technology, physicians gaining access to patients’ CGM data will recognize its positive effects, providing an important motivation for change.

Currently, even among people with diabetes in the United States, fewer than 10% use CGMs.

New Devices Are on the Way

Stelo will soon have competitors, as Abbott Diabetes Care prepares to introduce two new over-the-counter CGMs in the coming months.

Believing that no single approach to glucose monitoring is sufficient, Abbott developed two products. Lingo is designed for consumers seeking to improve their general health and well-being, while Libre Rio was developed for people with type 2 diabetes who do not use insulin and generally manage their condition through lifestyle changes.

Continuous Glucose Monitoring: Is It Necessary Only for Insulin Users?

It is increasingly understood that CGMs offer important benefits beyond insulin users. Metabolic health spans a broad spectrum: entirely healthy people, those at risk of diabetes because of family history or other medical factors, people with insulin resistance or prediabetes, and people with diabetes who do or do not use insulin. This broad audience must be considered when discussing and assessing CGM technology. The key question is: in which specific groups do the benefits outweigh the costs and potential harms? The more impaired metabolic health is, the greater the benefits of CGM.

The value of CGM for insulin users, who are consequently at risk of hypoglycemia, is now considered indisputable. Even among people not using insulin, debate has diminished as evidence grows that CGM provides biological feedback, encourages behavioral change, and supports learning. Hopefully, insurance coverage will expand over time to include more people whose metabolic health could improve through CGM.

However, there is not yet sufficient evidence of health benefits from CGM in people without medical problems, insulin resistance, or a family history of diabetes.

When deciding whether to spend healthcare funds on CGM or weight-loss injections, diabetes drugs will generally be the more effective choice. In an ideal world, access to both options could be supported. However, given the weight loss, cardiovascular improvement, and HbA1c reduction associated particularly with injections such as GLP-1 receptor agonists, these drugs appear to have stronger effects than CGM.