NO-Meal Announcement in Automated Insulin Delivery (Open-source and Commercial) Systems

Summary

Automated insulin delivery (AID) systems are the current gold standard for the management of type 1 diabetes (T1D), improving glycemic control, reducing hypoglycemia, and decreasing treatment burden. Although both commercial AID (C-AID) and open-source AID (OS-AID) systems have demonstrated significant clinical benefits, direct randomized comparisons between these systems remain scarce. Moreover, an important limitation of currently available AID systems is their reliance on user-initiated meal announcements and carbohydrate counting, which remain major contributors to postprandial dysglycemia and treatment burden. While emerging evidence suggests that AID systems may partially compensate for missed meal announcements, their comparative performance under these challenging real-world conditions is unknown.

The NOMAD study is an international, multicenter, open-label, randomized, non-inferiority crossover trial designed to compare an open-source AID system with commercially available AID systems (including Tandem Control-IQ and Omnipod 5) in adults with type 1 diabetes currently using an open-source AID system. The study specifically evaluates glycemic outcomes following standardized unannounced meal challenges performed under free-living conditions.

A total of 33 participants will be enrolled and complete two 4-week intervention periods, each consisting of a 2-week run-in phase followed by a 2-week data collection phase, with crossover between treatment arms. Participants will continue using their own Dexcom G6 or Dexcom G7 continuous glucose monitoring system throughout the study.

The primary outcome is the percentage of time spent in the target glucose range (3.9-10.0 mmol/L) during the 4 hours following standardized unannounced meal challenges. Secondary outcomes include additional CGM metrics (time above and below range, glucose variability, mean glucose, and GMI), insulin delivery characteristics, and patient-reported outcomes evaluating treatment satisfaction, usability, and diabetes-related burden.

Conditions

• Type 1 Diabetes (T1D)

Interventions

DEVICE

Open-Source Automated Insulin Delivery (OS-AID)

Participants will use their own OS-AID system, including Loop, AndroidAPS, or OpenAPS, in combination with a compatible insulin pump and Dexcom G6 or Dexcom G7 continuous glucose monitoring (CGM). These systems use open-source algorithms to automatically adjust insulin delivery based on real-time CGM data through adaptive basal insulin modulation and, depending on the platform, automated correction boluses. Participants will continue using their established OS-AID settings throughout the intervention period without software updates and will be asked to perform two unannounced meal-challenges.

DEVICE

Commercial Automated Insulin Delivery (C-AID)

Participants will use a commercially available hybrid closed-loop AID system compatible with Dexcom G6 or Dexcom G7 CGM. Depending on study allocation and participants' usual device, the commercial system will include Tandem t X2 with Control-IQ technology or Omnipod 5. Participants not already using a compatible commercial AID system will receive study equipment and standardized training before initiating the intervention. Commercial AID systems automatically adjust insulin delivery based on continuous glucose measurements using manufacturer-specific algorithms while continuing to recommend user-initiated meal announcements and boluses for optimal performance.

Sponsors & Collaborators

• Stanford University

  collaborator OTHER

• University of Alberta

  collaborator OTHER

• Institut de Recherches Cliniques de Montreal

  lead OTHER

Principal Investigators

• Rémi Rabasa-Lhoret, M.D. Ph.D · IRCM

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-10-01

Primary Completion

2029-09-01

Completion

2029-12-31

Countries

• Canada

Study Locations