Continuous glucose monitors are about to get more complicated

Abbott has received US Food and Drug Administration authorization for Libre Duo, a wearable sensor designed to track two measurements at once: glucose and ketones. The device adds a second biochemical warning channel to technology already widely used in diabetes care. For people at risk of diabetic ketoacidosis, the aim is to identify a potentially dangerous shift before symptoms become a medical emergency.

Continuous glucose monitors have generally been built around one task: showing glucose patterns throughout the day rather than relying solely on occasional finger-stick tests. Libre Duo extends that model to ketones, compounds produced when the body burns fat for energy. Abbott says the sensor measures beta-hydroxybutyrate, a ketone that can help signal when a person may be moving toward ketoacidosis.

Diabetic ketoacidosis, often shortened to DKA, develops when there is too little insulin for the body to use blood glucose as fuel. The liver may then turn to fat metabolism, producing ketones. Some ketone production is not automatically harmful, but a large buildup can make the blood dangerously acidic. DKA can advance quickly and can be fatal without treatment; it is especially associated with type 1 diabetes, though it can also occur in people with type 2 diabetes.

Ketone testing is already familiar in parts of diabetes care, particularly for children, but it has not been a routine priority for many adults. Traditional checks commonly use strips that provide a limited snapshot and may indicate a range by color rather than produce a continuous record. A sensor that couples ketone information with glucose data could put the alert in a format patients, family caregivers and clinicians already recognize.

Abbott says Libre Duo can be worn for up to 10 days. It uses the company’s existing app, can work with smartwatches, and permits caregivers to follow readings from a loved one. Those features could matter for families managing childhood diabetes, where DKA is a major concern. The same combined data may also be relevant to insulin-pump users, whose insulin supply can be interrupted by an unnoticed leak or connection failure.

Another possible use involves people taking SGLT2 inhibitors, medicines that lower blood sugar partly by helping the body eliminate excess glucose in urine. Clinicians have identified an uncommon situation in which someone using these drugs can develop ketoacidosis without markedly high glucose readings. That mismatch can make a glucose-only warning harder to interpret. A ketone signal could serve as an additional safeguard, although it would not replace clinical judgment or emergency care.

The expansion also brings familiar concerns from the broader CGM market. Patients have reported worries about sensor accuracy, alert fatigue and the challenge of deciding what an individual reading means. Some people with diabetes say they have gone years without needing to test ketones, while others fear that an erroneous alert could cause needless disruption. Adding a second continuously measured substance may increase useful information, but it may also increase the number of decisions users are asked to make.

Interpretation is likely to be an early test. A recent expert consensus has used 3 mmol/L as a point at which ketone levels warrant concern, but specialists acknowledge that the threshold reflects the best available guidance rather than a settled answer for every circumstance. Pregnancy, illness, fasting and strenuous exercise can all temporarily raise ketones without necessarily indicating DKA. Clinicians will need to distinguish meaningful danger signals from biological variation, and false-positive alerts remain a possibility.

For now, Libre Duo will require a prescription, according to Abbott, and the company has not announced an immediate move to sell it over the counter. Its arrival nevertheless illustrates a wider shift in wearables: sensors are increasingly intended to gather continuous metabolic data rather than a single measurement. The medical value may be considerable for people who need it, but the device’s success will depend on whether data, alerts and treatment advice can be made clear enough to help users without creating a new source of anxiety.

Source: The Verge