July 25, 2025

Leads:

Carol Levy – Mt. Sinai (Adult)

Emily Coppedge – Cornell (Peds)

Dr. Rayhan Lal, MD (Stanford Medicine) Discussed DIY Systems

Discussion on key takeaways, research findings, and implications for clinical practice
Q&A with Dr. Rayhan Lal

Open-Source Automated Insulin Dosing

Challenges with Automated Insulin Dosing

Data from the Omnipod 5 showed that only 28.3% of kids and 44.3% of adults were meeting both glucose targets.
Our fastest insulins are not much faster than our last gen insulins.
The time to when people bolus is more deviant than the delta that arises from faster insulins.

Regulatory and Data Ownership Barriers

The Class 2 regulatory environment at the FDA introduces special controls established by the company that develops the first device in their category.
People with diabetes don’t own their data.
HIPAA is obsolete because it defines health information as data residing in a designated record set maintained by a covered entity (health providers or plan), not large biotech companies.
Manufacturers are typically considered business associates, so device data does not enter the designated record set and exists in a legal gray area.
Medtech corporations act as gatekeepers, controlling access for people with chronic diseases, healthcare systems, researchers, and startups.

Commercial Algorithm Comparison

Loop, IAPs, and Trio

Loop Algorithm

The loop algorithm is straightforward and uses similar math to predict future glucose levels.
Future predicted glucose = IOB * ISF downward + (carbs on board / carb ratio) * ISF.
ISF over carb ratio is also known as carb sensitivity ratio.
Carb sensitivity ratio is well preserved for people at different ages.
Loop uses short-term adaptation through retrospective correction.
If the prediction is wrong, the delta is added to the next prediction.
Adaptation occurs over 5-15 minutes.
Loop may not be ideal for unannounced meals because adaptation takes time.
Highs may occur initially, followed by lows due to delayed pullback.

Therapy Settings

Open APS Filter

Open APS has a filter to avoid spurious points being taken as unannounced meals.
The default filter only accounts for glucose rises of 20%.
A glucose rise of 40% is generally okay unless there is a noisy G7.

Algorithm Settings

Adjustments

Loop

Turn on help integration and choose whether to share data.
Set Night Scout glucose safety limit (equivalent to 85).
Correction range is the target range.
Carb ratios and basal rates need to be set.
People new to these systems need assistance with physiology and diabetes-specific settings.
Assist with supplies and titration.

Choosing a System: Loop, Trio, or iAPS

Loop is better for Type A personalities who never miss a bolus.
Trio or APS is better for those who want diabetes to be secondary to the rest of their life.
These systems are good for those who don’t always remember to bolus.
Android APS and Trio/iAPS support unannounced meals.

Other topics that were covered: