NCT02241889

Three-way, Cross-over Closed-loop Exercise Study

A Randomized, Three-way, Cross-over Study to Assess the Efficacy of a Bi-hormonal Closed-loop System With vs Without Exercise Announcement vs Open-loop Therapy in Reducing Exercise-related Hypoglycemia

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 23 (actual)
• Sponsor: Oregon Health and Science University · Academic / Other
• Sex: All
• Age: 21 Years – 45 Years
• Healthy volunteers: Accepted

Summary

Blood glucose control systems that utilize both insulin and glucagon to manage blood sugar are paving the way to revolutionize the management of this disease. The benefit of improved control of blood sugar levels compared to standard insulin pump therapy has already been demonstrated. However, the risk of low blood sugar in type 1 diabetes increases considerably during exercise. The investigators research group has shown that small doses of glucagon can prevent low blood sugar when used in a blood sugar control system in patients with type 1 diabetes. However, as insulin sensitivity changes occur very rapidly during exercise, the ability to recognize the onset of physical activity in order to appropriately adjust the insulin and glucagon delivery is vital to helping prevent exercise-induced hypoglycemia. The purpose of this study is to test how well a new modified blood sugar control system controls blood sugar during exercise compared to: 1) the current system without modifications and 2) standard insulin pump therapy.

Detailed description

Subjects will exercise during three study visits. During one visit, blood sugar will be controlled using standard insulin pump therapy. The investigators blood glucose control system will manage blood sugar for subjects during the other visits, with exercise announcement with insulin and glucagon delivery modifications during one visit. Treatment order will be randomized. Heart rate and accelerometry data will also be collected during each visit for the purposes of designing an exercise detection system for future studies. Each subject will be asked to undergo an eligibility screening and to sign a consent form before any study procedures take place. At the screening appointment, after the consent form is signed, blood will be drawn for laboratory tests and a brief physical exam will be performed. An EKG and VO2max test will be completed at screening. Subjects that are enrolled in the study will come in for a sensor insertion visit up to 72 hours before each study visit. Subjects will undergo three 21-hour studies at an OHSU clinic or the OHSU clinical research center. Subjects will arrive at the research center at 8pm. Approximately 2 hours after a low-carbohydrate breakfast on Day 2, subjects will exercise for 45 minutes at 60% of their VO2max determined at screening. Three hours after completion of exercise, subjects will eat lunch. The study will end \~5 hours after lunch. Capillary blood glucose (CBG) will be measured every 2 hours during the day, every 3 hours at night and before and after exercise for studies using the blood glucose control system with subjects blinded to the CBG values. For studies using insulin pump therapy, the subject will sample CBG four times during the day as well as before and after exercise. Study staff will monitor studies remotely using a cloud server. An investigator or nurse practitioner with a specialty in endocrinology or internal medicine will be on site (located within the same complex) at all times.

Conditions

• Type 1 Diabetes

Interventions

Type	Name	Description
DEVICE	Insulin pump therapy	Subject's own insulin pump will be used to manage blood glucose.
DEVICE	Closed-loop Artificial Pancreas Controller	Closed-loop Artificial Pancreas Controller includes insulin and glucagon delivery algorithm implemented on a smart phone, utilizing sensor glucose values from a Dexcom G4 sensor and sending delivery commands to two Tandem t:slim insulin pumps, one filled with insulin and one with glucagon.

Timeline

• Start date: 2015-01-01
• Primary completion: 2015-09-01
• Completion: 2015-09-01
• First posted: 2014-09-16
• Last updated: 2017-05-22
• Results posted: 2017-05-22

Locations

1 site across 1 country: United States