Using a Personalized Decision Support Tool to Help People With Type 1 Diabetes Manage Exercise

NCT07226583 | Not Yet Recruiting FDA Device

• 2 other identifiers: 822242407-07175
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This study evaluates a clinician-facing decision-support toolkit designed to assist adults with type 1 diabetes in preparing for moderate-intensity exercise. The netIOB \& Exercise Toolkit (NEXT) integrates recent glucose data and insulin delivery history to provide individualized suggestions regarding exercise timing, insulin adjustments, and carbohydrate intake. Adults with type 1 diabetes will complete three supervised exercise sessions under different pre-exercise guidance approaches: (A) published consensus-based standard-of-care guidance, (B) usual personal care routines, and (C) guidance informed by the NEXT Toolkit. A healthy adult control group will complete a single supervised exercise session to provide comparative physiologic data.

Conditions

Type 1 Diabetes Mellitis; Type 1 Diabetes (T1D); Type 1 Diabetes Mellitus (T1DM); Exercise Physiology

Keywords

Type 1 Diabetes; T1D; T1DM; Continuous Glucose Monitoring; Insulin Dosing; CGM; Insulin Pump; Exercise; carbohydrate Intake; closed-loop system; hybrid closed-loop

Outcome Measures

Primary Outcomes (1)

• Composite Score of Glycemic Safety and Carbohydrate Burden

  This composite outcome reflects glycemic risk during exercise and the subsequent post-exercise monitoring period. The score is based on a Magni risk-derived metric computed from continuous glucose monitoring (CGM) data, with the glycemic effects of rescue carbohydrate treatments removed to isolate underlying glycemic risk. Each evaluated timepoint is given a score ranging from 0 to 100, where lower scores indicate lower glycemic risk and higher scores indicate higher glycemic risk. Scores across the defined observation windows are summarized across intervention conditions.

  Baseline (1 hour pre-exercise), Exercise (0 to 90 minutes), Early Post-Exercise (0 to 6 hours after exercise), Mid Post-Exercise (6 to 24 hours after exercise), Late Post-Exercise (24 to 48 hours after exercise); total of 50.5 hours per visit (3 visits).

Secondary Outcomes (11)

• Percent-Based Continuous Glucose Monitor Metrics

  Baseline (1 hour pre-exercise), Exercise (0 to 90 minutes), Early Post-Exercise (0 to 6 hours after exercise), Mid Post-Exercise (6 to 24 hours after exercise), Late Post-Exercise (24 to 48 hours after exercise); total of 50.5 hours per visit (3 visits).

• Glucose Concentration and Variability Metrics from Continuous Glucose Monitor

  Baseline (1 hour pre-exercise), Exercise (0 to 90 minutes), Early Post-Exercise (0 to 6 hours after exercise), Mid Post-Exercise (6 to 24 hours after exercise), Late Post-Exercise (24 to 48 hours after exercise); total of 50.5 hours per visit (3 visits).

• Frequency of Hypoglycemic Events

  Exercise (0 to 90 minutes), Early Post-Exercise (0 to 6 hours after exercise); total of 7.5 hours per visit (3 visits).

• Glucose Nadir Value

  Exercise (0 to 90 minutes), Early Post-Exercise (0 to 6 hours after exercise); total of 7.5 hours per visit (3 visits).

• Time to First Hypoglycemic Event

  Exercise (0 to 90 minutes), Early Post-Exercise (0 to 6 hours after exercise); total of 7.5 hours per visit (3 visits).

Study Arms (4)

Standard-of-Care (SoC)

OTHER

Participants follow consensus-based guidance for insulin and carbohydrate adjustments around exercise, as outlined in current international standards. These recommendations are applied by study staff in advance of the exercise session.

Behavioral: Standard-of-Care Guidance (SoC); Device: Continuous Glucose Monitoring; Device: Continuous Ketone Monitoring

Usual Care (UC)

OTHER

Participants use their own strategies for managing insulin and carbohydrate around exercise.

Behavioral: Usual Care (UC); Device: Continuous Glucose Monitoring; Device: Continuous Ketone Monitoring

netIOB & Exercise Toolkit (NEXT)

EXPERIMENTAL

Physicians receive personalized, algorithm-informed recommendations for exercise-related insulin and carbohydrate adjustments. Recommendations are generated using the investigational netIOB \& Exercise Toolkit based on CGM data, insulin history, and real-time inputs.

Device: netIOB & Exercise Toolkit (NEXT); Device: Continuous Glucose Monitoring; Device: Continuous Ketone Monitoring

Healthy Control

OTHER

Adults without diabetes complete one supervised moderate-intensity exercise session for physiologic comparison.

Device: Continuous Glucose Monitoring; Device: Continuous Ketone Monitoring

Interventions

Standard-of-Care Guidance (SoC) BEHAVIORAL

Study staff provide insulin and carbohydrate adjustment advice based on consensus exercise management guidelines (Moer et al., 2024), tailored to the planned activity.

Standard-of-Care (SoC)

Usual Care (UC) BEHAVIORAL

Participants independently manage their insulin and carbohydrate decisions around exercise, using their routine practices without study-provided guidance.

Usual Care (UC)

netIOB & Exercise Toolkit (NEXT) DEVICE

An investigational software tool generates individualized insulin and carbohydrate adjustment recommendations before and after exercise using CGM data and recent insulin delivery. Study physicians review and relay these recommendations to participants.

netIOB & Exercise Toolkit (NEXT)

Continuous Glucose Monitoring DEVICE

Continuous glucose monitoring using an FDA-cleared system (Dexcom G7) for research data collection during and after exercise. CGM data are used to assess glycemic responses and are not used to evaluate device performance or accuracy.

Healthy Control; Standard-of-Care (SoC); Usual Care (UC); netIOB & Exercise Toolkit (NEXT)

Continuous Ketone Monitoring DEVICE

Investigational dual-analyte continuous glucose-ketone monitoring device used for continuous ketone data collection only during and after exercise. Glucose data generated by the device are not used for analysis or clinical decision-making. Ketone data are collected for exploratory research purposes only and are not used to assess device performance or accuracy.

Healthy Control; Standard-of-Care (SoC); Usual Care (UC); netIOB & Exercise Toolkit (NEXT)

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Adults between the age of 18-60 years
• Able to perform moderate intensity walking for 60 minutes (target 40-60% age-predicted maximal heart rate).
• Willing and able to comply with study procedures, including supervised exercise visits and device wear
• Able to provide written informed consent
• Clinical diagnosis of type 1 diabetes for \>1 year, based on the investigator's clinical judgement
• Current use of continuous subcutaneous insulin infusion with Tandem Control-IQ and a compatible continuous glucose monitor (CGM) for \>1 month prior to enrollment
• Stable insulin delivery regimen, with no planned changes to insulin pump settings or insulin dosing strategy during the study period
• Consistent CGM use during the month prior to enrollment (\>80% data availability)
• No diagnosis of diabetes or other disorders of glucose metabolism
• Not using insulin or glucose-lowering medications

You may not qualify if:

• Intercurrent illness or medical condition that precludes safe participation in moderate-intensity exercise (e.g., unstable cardiopulmonary disease, uncontrolled arrhythmia, or uncontrolled hypertension), as previously assessed by the participant's primary care physician
• Known coronary artery disease with symptoms limiting moderate physical activity, or history of myocardial infarction, percutaneous coronary intervention, or coronary artery bypass grafting within the past 12 months
• Pregnancy, lactation, or plans to become pregnant during the study period
• Renal insufficiency with estimated GFR \<45 mL/min/1.73 m², dialysis dependence, or adrenal insufficiency
• Concurrent participation in another interventional drug or device study within 30 days prior to enrollment
• Inability to comply with study procedures or safety requirements (e.g., inability to achieve target heart-rate zone, attend scheduled visits, or enable required device data access), or otherwise deemed unsuitable by the investigator
• Use of non-CSII insulin delivery, including long-acting injectable or inhaled insulin, during the study period
• Use of medications with potential to substantially affect glycemia (e.g., SGLT-2 inhibitors, GLP-1 receptor agonists, or GIP agonists), unless on a stable regimen with no planned changes during the study
• Use of systemic corticosteroids within 4 weeks prior to participation
• History of severe hypoglycemia (requiring third-party assistance) or diabetic ketoacidosis within the prior 6 months

Sponsors & Collaborators

• Stanford University: lead
• University College Dublin: collaborator
• The Leona M. and Harry B. Helmsley Charitable Trust: collaborator

Study Sites (1)

Stanford University

Palo Alto, California, 94304, United States

Location

MeSH Terms

Conditions

Diabetes Mellitus, Type 1; Motor Activity

Interventions

Continuous Glucose Monitoring

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases; Behavior

Intervention Hierarchy (Ancestors)

Blood Chemical Analysis; Clinical Chemistry Tests; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Diagnostic Techniques, Endocrine; Monitoring, Physiologic; Investigative Techniques

Study Officials

• Rayhan Lal, MD

  Stanford University

  PRINCIPAL INVESTIGATOR

• Dessi dessi@stanford.edu, PhD

  Stanford University

  STUDY DIRECTOR

Central Study Contacts

Dessi Zaharieva, PhD

CONTACT

628-238-9420; dessi@stanford.edu

Ryan Kingman, BS

CONTACT

650-736-4417; rkingman@stanford.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: It is not feasible to blind participants or staff to the intervention being applied for each session.
• Purpose: SUPPORTIVE CARE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor of Medicine & Pediatrics

Model Details: Participants with type 1 diabetes complete three supervised moderate-intensity exercise visits in a randomized, three-period crossover design, with each visit conducted under a different pre-exercise management strategy (standard-of-care guidance, usual care, or the NEXT decision-support toolkit). Visits are separated by a washout period to minimize physiologic carryover. In addition, a healthy adult control group completes a single supervised exercise visit without randomization to provide comparative physiologic data.

Study Record Dates

• First Submitted: October 7, 2025
• First Posted: November 10, 2025
• Study Start: April 1, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026
• Last Updated: February 19, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: Data will be available beginning 18 months after article publication and ending 5 years following article publication.
• Access Criteria: Proposals should be directed to dessi@stanford.edu. To gain access, data requestors will need to sign a data access agreement.

Locations

US (1)