Preventing Hypoglycemia During Exercise With Proactive Snacking on Closed Loop

Early Phase 1

Completed

• Conditions: Type 1 Diabetes
• Interventions: Device: Medtronic MiniMed Closed Loop (CL) System; Other: Snacking

• Registration Number: NCT02135068
• Lead Sponsor: Yale University

Brief Summary

This study is designed to look at how snacking during exercise may help prevent low blood sugars while subjects are on the "closed loop artificial pancreas." This system uses a continuous glucose sensor, an insulin pump, and a computer program that automatically determines how much insulin to give based on the sensor glucose level.

Detailed Description

This study will be a randomized cross-over study as subjects will be studied under both study conditions - Closed Loop (CL) alone vs. CL + proactive snacking protocol). Differences in the nadir blood glucose levels during exercise between the two study conditions will be the primary outcome measure.

Study Timeline

• Study First Submitted: 2014-04-16
• Study First Submitted QC: 2014-05-07
• Study First Posted: 2014-05-09
• Study Start: 2015-01
• Primary Completion: 2016-06
• Study Completion: 2016-12
• Status Verified: 2020-04
• Last Update Submitted: 2020-04-16
• Last Update Posted: 2020-04-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 15

Inclusion Criteria

1. Age 13-45 years
2. Clinical diagnosis of T1D (formal antibody and/or genetic testing will not be required)
3. Duration of T1D ≥ 1 year
4. HbA1c ≤ 9 %
5. Treated with continuous subcutaneous insulin infusion (pump) for at least 3 months
6. Body weight > 40 kg (to accommodate phlebotomy)
7. Able to tolerate a 75-minute exercise period of moderate intensity
8. Be willing to wear 2 subcutaneous glucose sensors (placed under the skin like a pump site) simultaneously during the inpatient portions of this study.
9. Be in good general health without other acute or chronic illness that in the judgment of the investigator could interfere with the study or jeopardize subject safety
10. Normal hematocrit
11. Able to give consent (for children <18 years, permission from parents and subject assent will be required)
12. Female subjects of reproductive potential must be abstinent or consistently using appropriate family planning methods.

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Exclusion Criteria

1. Insulin resistant (defined as requiring > 1.5 units/kg/day at time of study enrollment)
2. Presence of any medical or psychiatric disorder that may interfere with subject safety or study conduct
3. Use of any medications (besides insulin) known to effect blood glucose levels, including oral or other systemic glucocorticoid therapy. Inhaled, intranasal, or rectal corticosteroid use is allowed along as not given within 2 weeks of the closed loop admissions. Use of topical glucocorticoids is allowable as long as affected skin area does not overlap with study device sites.
4. Subjects using herbal supplements will be excluded, due to the unknown effects of these supplements on glucose control
5. History of hypoglycemic seizure within last 3 months
6. Female subjects who are pregnant, lactating, or unwilling to be tested for pregnancy

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
CL and exercise with proactive snacking	Snacking	Subject will consume oral glucose prior to starting exercise regimen while on the Medtronic MiniMed Closed Loop (CL) System
CL and exercise without proactive snacking	Medtronic MiniMed Closed Loop (CL) System	Subject will not consume oral glucose prior to starting exercise regimen while on the Medtronic MiniMed Closed Loop (CL) System
CL and exercise with proactive snacking	Medtronic MiniMed Closed Loop (CL) System	Subject will consume oral glucose prior to starting exercise regimen while on the Medtronic MiniMed Closed Loop (CL) System

Primary Outcome Measures

Name	Time	Method
Nadir blood glucose levels during exercise	75 minutes	Difference in the nadir blood glucose levels during exercise between the two study conditions: Closed Loop alone vs. Closed Loop+ snacking.

Secondary Outcome Measures

Name	Time	Method
Nadir glucose levels overnight	12 hours	Difference between nadir glucose levels between the two study conditions will be assessed.
Episodes of hypoglycemia (blood glucose <60mg/dL) during exercise	75 minutes	Percentage of subjects that required treatment for hypoglycemia during the exercise period between the two study conditions
Mean absolute relative difference (MARD) for each sensor	24 hours	Calculation and comparison of the mean absolute relative difference for each sensor will be performed and comparisons between accuracy of the sensors will be done.
Mean reduction in blood glucose during exercise	75 minutes	Mean Reduction in blood glucose from baseline blood glucose during exercise
insulin delivery during CL therapy	24 hours	Differences between insulin delivery during CL therapy during the two study conditions (pro-active snacking vs. no snacking) will be assessed.
Mean time blood glucose in target during exercise	75 minutes	Comparison of the mean time blood glucose levels were between 70-180mg/dL during exercise between the two study conditions
Mean glucose values	12 hours	Comparison of the mean daytime and nighttime glucose values
Mean 24- hour glucose levels	24 hours	Comparison of the mean 24- hour glucose levels
Nadir glucose levels following the meals	24 hours	Nadir glucose levels following meals will be compared between the two study conditions
Area under the curve meal-related plasma insulin level excursion following meals	24 hours	Area under the curve meal-related insulin excursion following meals.
Mean time blood glucose levels are in target during the overnight period	17 hours	Comparison of the mean time blood glucose levels are in target (70-180mg/dL) during the overnight period after mid-afternoon exercise.
Incremental meal-related glucose Area Under the Curve	24 hours	Assessment of incremental meal related glucose area under the curve will be conducted.
Mean daytime and nighttime glucose values	24 hours	Comparison of the mean daytime and nighttime glucose levels

Trial Locations

Locations (1)

Yale University School of Medicine; 🇺🇸 New Haven, Connecticut, United States