Long-term Observation of Patient Engagement in Automated Insulin Delivery

Recruiting

• Conditions: Type 1 Diabetes Mellitus

• Registration Number: NCT06858475
• Lead Sponsor: Centre Hospitalier Sud Francilien

Brief Summary

The purpose of this study is to assess the long-term evolution of patient interaction with the CONTROL-IQ (Tandem™) hybrid closed-loop (HCL) system in individuals with type 1 diabetes over 24 months. Specifically, the study examines user-initiated boluses and carbohydrate announcements to determine whether initially low-engagement users increase their involvement over time or, conversely, whether highly engaged users gradually rely more on automation.

Detailed Description

Automated insulin delivery (AID) systems have revolutionized type 1 diabetes (T1D) management, offering superior glycemic control and quality of life compared to sensor-augmented insulin pumps or multiple daily injections (MDI). However, current AID systems operate as hybrid closed-loop (HCL) systems, requiring user intervention for meal boluses, including carbohydrate counting and timely insulin administration.

Control-IQ (Tandem™) was the second AID system reimbursed by the French National Health Insurance and is now widely used in France. It combines the Tandem™ t:slim insulin pump with Dexcom™ G6 continuous glucose monitoring (CGM), adjusting basal insulin every five minutes based on glucose predictions and delivering automatic correction boluses once per hour. Despite these automation features, users must still manually initiate meal boluses, and additional correction boluses remain optional. While engagement in carbohydrate counting and timely meal announcements improves metabolic outcomes, real-world data suggest that AID benefits individuals across varying engagement levels.

Long-term data on patient behavior and engagement, particularly regarding carbohydrate announcements and the ratio of automatic to user-initiated boluses, remain limited. Understanding these patterns could reveal whether initially low-engagement users increase involvement over time or whether highly engaged users eventually rely more on automation.

This single-center, 24-month observational study will follow all T1D patients treated with Control-IQ at the Centre Hospitalier Sud-Francilien between October 2021 and October 2024.

Study Timeline

• Study First Submitted: 2025-02-21
• Study First Submitted QC: 2025-02-27
• Status Verified: 2025-03
• Study First Posted: 2025-03-05
• Study Start: 2025-03-20
• Last Update Submitted: 2025-03-20
• Last Update Posted: 2025-03-21
• Primary Completion: 2025-12-31
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 453

Inclusion Criteria

• Patients using the CONTROL-IQ hybrid closed-loop system with data uploaded to the myDiabby platform at least once between October 2021 and October 2024, affiliated with the diabetology department of CHSF.

Exclusion Criteria

• Patients with a type of diabetes other than type 1 diabetes.
• Patients who have objected to the use of their data.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
number of automatic boluses	repeated measurement over 24 months (8 quarters)	To assess the 24-month evolution of the automatic-to-user-initiated bolus ratio

Secondary Outcome Measures

Name	Time	Method
time spent in closed-loop mode	repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of the percentage of time spent in closed-loop mode (CONTROL-IQ ON)
insulin dose (UI)	repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of the average of total daily insulin dose (UI)
carbohydrates	repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of the average amount of carbohydrates reported daily in closed-loop mode (CONTROL-IQ).
glucose	Repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of continuous glucose monitoring parameters, including average glucose in closed-loop mode (CONTROL-IQ).
glucose management indicator	Repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of continuous glucose monitoring parameters, including average glucose management indicator in closed-loop mode (CONTROL-IQ).
glucose coefficient of variation	Repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of continuous glucose monitoring parameters, including glucose coefficient of variation in closed-loop mode (CONTROL-IQ).
percentage of time in target range (70-180 mg/dL)	Repeated measurement over 24 months (8 quarters)	Measurement of the quarterly evolution, over 24 months, of continuous glucose monitoring parameters, including percentage of time in target range (70-180 mg/dL) in closed-loop mode (CONTROL-IQ).

Trial Locations

Locations (1)

Centre Hospitalier Sud Francilien; 🇫🇷 Corbeil-essonnes Cedex, France