September 26, 2025

Leads:

Carol Levy – Mt. Sinai (Adult)

Emily Coppedge – Cornell (Peds)

Agenda:

Background on Ketones

Ketones are breakdown products of fat and are acidic.
They occur at higher rates during fasting and in people with diabetes due to a relative lack of insulin.

Diabetic Ketoacidosis (DKA)

DKA is caused by ketone buildup.
Diagnostic criteria include hyperglycemia (glucose >200 mg/dL, lowered from 250 mg/dL) and a prior history of diabetes can substitute for a specific glucose level.
DKA is classified as mild, moderate, and severe, primarily based on pH levels (ISPAD) and other criteria (joint consensus statement).

Why AID Users Develop Ketones

A primary reason is relative insulin deficiency, often due to issues related to the underlying situation of the patient or missed insulin.
Pump-specific reasons include infusion site failures (kinking, dislodgement), battery failures, empty insulin cartridges, and prolonged insulin suspensions (manual or algorithm-related).
Example: A teenage patient on a Tandem system experienced multiple occlusion alarms (leading to temporary insulin suspensions), running out of insulin, and battery failures within a week.
Illnesses, stress, trauma, and prolonged fasting can also lead to ketone development.
DKA is a concern for anyone with diabetes.
A Swedish study on children found that most DKA admissions were in pump users, which may correlate with the high pump usage in the population.
Pump users had milder DKA, while moderate to severe DKA was more evenly distributed between pump and MDI users.
DKA Rates in Closed Loop vs. Open Loop
DPV data (approx. 14,000 patients) showed higher DKA rates in closed loop systems compared to open loop, despite lower A1C levels in closed loop users.
US-based report (approx. 15,000 admissions) found DKA rates were similar between pump users (20.9%) and injection users (20.4%).

Ketone Testing Methods

General Treatment for Ketones

Ketone Management with AID Systems

Fully closed loop systems aim to minimize user engagement, but this may reduce awareness and delay action.
Prolonged insulin suspensions due to hypoglycemia or fasting may lead to unchecked ketone development.
Insufficient insulin delivery due to false CGM data or limited/safe modes.
A recent report showed that not all institutions had defined protocols for ketone management, especially for AID systems or pumps.
Educate patients to change infusion sites if they have prolonged hyperglycemia with ketone development and no other explanation. “I always tell people to change your infusion site out first and foremost.”
Adjust alarms to avoid low cartridges, especially for kids. Set the low volume alarm to alert them when they hit a certain value, considering their overnight insulin needs.
Remind patients to check insulin volume and battery life regularly, ideally as part of their bedtime routine.

Pump-Specific Issues

Islet does not have correction dosing or manual boluses. Using the meal dosing bolus for highs and ketones can mess up mealtime calculations.
Recommend injection doses for ketones and corrections and disconnecting from the pump.
Medtronic does not allow for manual boluses while in SmartGuard; users must switch to manual mode.
Tandem and Omnipod both allow for overriding of bolus doses within automation.

Protocols for AID vs. General Pump Use

There is debate on whether separate protocols are needed for aid systems versus general pump use.
The major issue with ketone management is the lack of basic steps, such as changing infusion sets and giving an initial injection dose.
Reinforce these steps with all pump and aid users.

Concerns with AID and Injected Insulin

Due to the glucose-responsive nature of aid systems, injected insulin can cause the algorithms to decrease insulin delivery or even suspend it.
The pump does not account for injected insulin in its insulin-on-board calculations.
It is uncertain whether automation can adapt to the drop in glucose and avoid giving excessive additional insulin.
Insulin needs are high during ketosis, so the risk of true hypoglycemia may be low.
There is limited real-world data on this topic.

Barbara Davis Center Protocol

The PANTHER program developed a hyperglycemia protocol with an insulin pump, available on their website, used with general sick day guidelines.
For small ketone levels (less than 1), patients can continue using their pump and bolusing.
Once ketones develop, it is recommended to administer an insulin injection via pen or syringe, change the infusion set, and monitor glucose and ketone levels frequently.
For extra-large ketones, continue injections, discontinue pump use, change the site, and contact the diabetes on-call team if there is no improvement after a couple of hours.

Future of Ketone Monitoring

A dual glucose-ketone sensor is currently under review, with the goal of availability next year.
Considerations include determining appropriate alert levels, as continuous ketone data at all times may not be necessary.
There is ongoing discussion about how continuous ketone monitoring will integrate into pump use and aid systems.
The aid automation may have limited impact if the infusion site has failed.
Continuous ketone data may provide early notification of ketone development, prompting earlier infusion site changes.
SQL Twist and Tandem Control IQ systems plan to integrate Abbott dual glucose-ketone sensor data, initially as a data display and alarm system.

Long Suspensions in EIDs

A question was raised about long suspensions in EIDs, especially in young children with low insulin needs.
There is concern about prolonged suspensions and the potential for ketone production, especially in very young children on pumps.
If prolonged periods of insulin suspension are observed, consider a morning ketone test or continuous ketone monitoring.

Other topics:

Group Discussion:

UT Southwest Protocol

UT Southwest’s protocol emphasizes pump site change and injection.
They disconnect from islet for two hours after injection.
They use temp target or exercise mode for two hours post-injection on other pumps.
They don’t teach air boluses.
Coaching point: ensure glucose levels decrease by sensitivity factor two hours post-injection.

DKA Admissions & Pump Users

A broadening audience is using pumps with varying learning levels.
Two-week visits should emphasize ketone management, not just dose titration.
Patients practice rescue dose scenarios on day one, especially those transitioning to pumps early.
Some patients are less skilled in rescue dosing.

Insulin Injections