Clinical trial NCT02135068: Preventing Hypoglycemia During Exercise With Proactive Snacking on Closed Loop
Official title: Preventing Hypoglycemia During Exercise With Proactive Snacking on Closed Loop
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: EARLY_PHASE1
Conditions: Type 1 Diabetes
Keywords: type 1 diabetes
closed loop insulin delivery systems
exercise
hypoglycemia
Lead sponsor: Yale University
Sponsor class: OTHER
Collaborators: name: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
First posted: 2014-05-09
Enrollment: 15
Sex: ALL
Minimum age (years): 13
Maximum age (years): 44
Standard ages: CHILD
ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

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.

Eligibility criteria: 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.

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

Primary outcomes:
measure: Nadir blood glucose levels during exercise
timeFrame: 75 minutes
Secondary outcomes:
measure: Episodes of hypoglycemia (blood glucose <60mg/dL) during exercise
timeFrame: 75 minutes
measure: Mean reduction in blood glucose during exercise
timeFrame: 75 minutes
measure: Mean time blood glucose in target during exercise
timeFrame: 75 minutes
measure: Mean time blood glucose levels are in target during the overnight period
timeFrame: 17 hours
measure: Mean glucose values
timeFrame: 12 hours
measure: Mean 24- hour glucose levels
timeFrame: 24 hours
measure: insulin delivery during CL therapy
timeFrame: 24 hours
measure: Incremental meal-related glucose Area Under the Curve
timeFrame: 24 hours
measure: Nadir glucose levels following the meals
timeFrame: 24 hours
measure: Area under the curve meal-related plasma insulin level excursion following meals
timeFrame: 24 hours
measure: Nadir glucose levels overnight
timeFrame: 12 hours
measure: Mean absolute relative difference (MARD) for each sensor
timeFrame: 24 hours
measure: Mean daytime and nighttime glucose values
timeFrame: 24 hours
Other outcomes:
Locations:
city: New Haven
country: United States
facility: Yale University School of Medicine
state: Connecticut
Study officials:
affiliation: Yale University
name: Jennifer Sherr, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References: