Disclosures: Alva reports he is an employee of Abbott. Klonoff reports he is a consultant to EOFlow, Fractyl, Lifecare, Novo Nordisk, Roche, Samsung and Thirdwayv. Please see the study and analysis for all other authors’ relevant financial disclosures.
May 13, 2021
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Continuous ketone monitoring may provide early identification of DKA

Disclosures: Alva reports he is an employee of Abbott. Klonoff reports he is a consultant to EOFlow, Fractyl, Lifecare, Novo Nordisk, Roche, Samsung and Thirdwayv. Please see the study and analysis for all other authors’ relevant financial disclosures.
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A continuous ketone monitor sensor provided ketone level results similar to a ketone test strip during a 14-day period, according to a study published in the Journal of Diabetes Science and Technology.

The sensor, develop by Abbott, is similar in structure and dimensions to a continuous glucose monitor, but was modified to measure beta-hydroxybutyrate levels in the subcutaneous tissue and store the ketone signal in its memory for transfer to a receiver.

Glucose test Adobe
Source: Adobe Stock

“Measuring urine or blood ketone levels using a strip-based technology has its limitations,” Shridhara Alva, PhD, senior director for clinical affairs at Abbott Diabetes Care, and colleagues wrote. “It provides episodic information that confirms an already ongoing ketosis or a diabetic ketoacidosis event. Early identification of production of ketones may warn of impending ketoacidosis that could reduce the complications of DKA and perhaps even prevent it.”

Researchers measured the in vitro sensitivity of the sensor by submerging 16 sensors in a solution of 100 mM of phosphate buffer at a temperature of 37°C. The stability of the sensor was assessed by submerging 16 sensors into phosphate buffer with 8 mM of ketone at 37°C for a period of 14 days.

For the clinical study, 12 volunteers (11 women; mean age, 32.3 years) were recruited at the Sansum Diabetes Research Institute in Santa Barbara, California. Participants maintained a low-carbohydrate, ketogenic diet throughout the study. Each participant had two sensors placed on the back of both upper arms and wore them for up to 14 days. Three sensors on each person were functional continuous ketone monitors, and one was a nonfunctional sensor measuring the in vivo background current. Participants performed eight daily finger-stick measurements with Precision Xtra ketone test strips. The test strip measurements were used for reference ketone readings.

Ketone sensor accurate over 14-day period

In the in vitro study, the sensors responded to changes in ketone concentration in a mean 228 seconds of adding ketone aliquots to the testing solution. The sensor signal was also stable, with an average daily signal loss of 0.15%, or 2.1% during a 14-day period.

In the clinical study, data were available for 31 of 36 ketone sensors and 11 of 12 background sensors. A total of 3,132 datapoints were collected during the study period, with 83.4% of the ketone sensor results coming within 0.225 mM of the reference measurements and 91.7% of the sensor results measuring within 0.3 mM of the reference. The overall mean absolute difference between the sensor and reference ketone concentrations was 0.129 mM.

“Expansion of sensing technology to analytes other than glucose will allow medical and lifestyle management of additional analytes of interest,” the researchers wrote. “Demonstration of feasibility of a ketone sensor is a significant step toward that goal. However, more work is necessary to evaluate the performance against independent plasma reference as well as demonstrate that these sensors will work effectively in conditions of DKA and in a wider dynamic range.”

Clinical implications for continuous ketone monitoring

In a related analysis article, David C. Klonoff, MD, medical director of the Diabetes Research Institute at Mills-Peninsula Medical Center in San Mateo, California, and colleagues said a continuous ketone monitor could provide several benefits for DKA prevention and management.

David C. Klonoff

“If a person with early DKA can be warned that their ketone levels are rising or that they are above a dangerous threshold, then the person can seek immediate assistance from their physician or a nearby emergency room,” Klonoff told Healio. “Knowing that they are becoming ill with DKA can allow a person to seek assistance earlier than they might otherwise have, and in some cases before they even feel very sick. The earlier a person with DKA realizes they are ill and goes for treatment, the better their chances are for a safe recovery.”

The benefits of a continuous ketone monitor could extend outside of DKA as well. Klonoff said a ketone monitor may one day be integrated with a CGM or an insulin pump all on the same piece of hardware to provide a more detailed metabolic profile for the wearer. For people on a very low-carbohydrate diet, a continuous ketone monitor could allow wearers to monitor a rise in ketone level and how much their diet is affecting their metabolism.

“Additional testing will be needed to understand the most useful clinical scenarios to use this system,” Klonoff said. “For people with type 1 diabetes, I would like to see more data on how quickly ketone levels can rise to dangerous levels when no insulin is available and how quickly ketone levels can fall again down to safe levels when insulin is resupplied. I would also like to see how steeply the population’s incidence of DKA will fall if people who are at high risk of this problem were to wear a continuous ketone monitor.”

Reference:

Zhang JY, et al. J Diabetes Sci Technol. 2021;doi:10.1177/19322968211009860.

For more information:

David C. Klonoff, MD, can be reached at dklonoff@diabetestechnology.org.