Closed-loop Glucose Control for Automated Management of Type 1 Diabetes

Not Applicable

Completed

Conditions: Type 1 Diabetes

Interventions: Device: Closed-loop

Registration Number: NCT00811317

Lead Sponsor: Boston University Charles River Campus

Brief Summary: We hypothesize that our integrated closed-loop glucose-control system can provide effective, tight, and safe blood glucose (BG) control in type 1 diabetes, thereby establishing the feasibility of closed-loop BG control.

Detailed Description: This study investigates the utility of an integrated closed-loop glucose-control system for regulating BG in type 1 diabetic subjects. The closed-loop system utilizes sub-cutaneous infusion or insulin and glucagon under the control of a computer algorithm. The only inputs to the algorithm are the subject weight and BG values measured every five minutes. Subjects will undergo up to three 27 hour GCRC admissions during which they will consume three standardized meals. Subject may participate in up to two closed-loop visits (with different insulin lispro pharmacokinetic parameter settings in the control algorithm) and some subjects will participate in open-loop visits. During the closed-loop admission BG will be controlled by the closed-loop system. During the open-loop visit subjects will regulate their own BG in the usual function using their insulin pumps. A small group of non-diabetic subjects will undergo a single 27 hour GCRC admission during which they will eat the same standardized meals. During all admission BG will be measured every 5 minutes and blood will be collected for measurement of insulin and glucagon levels every 10 minutes. During the closed-loop admission of diabetic subjects and the single admission of non-diabetic subjects, three commercially available continuous glucose monitoring devices will be worn. The data from these devices will later be compared to reference BG data.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 11

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Closed-loop	Closed-loop	Type 1 diabetic subjects under closed-loop blood glucose control

Primary Outcome Measures

Name	Time	Method
Average Blood Glucose Over the Closed-loop Control Period	24 hours

Secondary Outcome Measures

Name	Time	Method
Number of Carbohydrate Interventions	24 hours
Blood Glucagon Levels	24 hours
Glucagon T-max	24 hours	Time to maximum peak glucagon concentration
Sensitivity for Hypo- and Hyperglycemia of the CGM Devices Using the BG Measurement as the Standard	24 hours	Mean absolute relative difference (MARD) of CGM and BG glucose readings in hypoglycemia (\< 70 mg/dl) and hyperglycemia (\>180 mg/dl) in three different CGM devices: Dexcom, Navigator and Guardian
Peak Hyperglycemia Following Each Meal	After each of 3 meals
Percentage of Time Spent Within 70-180 mg/dl	24 hours
Percentage of Peak Post-prandial Hyperglycemias < 180 mg/dl (ADA Target)	24 hours
Percentage of Time Spent With BG < 70 mg/dl	24 hours
Nadir Blood Glucose Level for Each Hypoglycemic Event	24 hours
Total Insulin Dose	24 hours
Average Glucose and Glycemic Variability (MAGE) During Closed Loop Control in Diabetic Subjects Compared to the Comparable 24-hour Period the Day Prior to Admission as Measured by Navigator CGM Data	24 hours
Percentage of Time Spent in Hyperglycemia (BG> 180 mg/dl) After Meals	After each of 3 meals
Total Glucagon Dose	24 hours
Number of Participants Achieving a Stable Glucose Response to Insulin Dosing Around Idle Times Prior to Meals	24 hours
Accuracy of the Continuous Glucose Monitor (CGM) Using Blood Glucose Measurement as the Standard	24 hours	Measuring the mean absolute relative difference (MARD) between the blood glucose measurement and CGM glucose readings, on three different CGM devices: Dexcom, Guardian and Navigator
Average Glucose and Glycemic Variability During Closed Loop Control in Diabetic Subjects Compared to the Comparable 24 Hour Period in Non-diabetic Subjects	24 hours
Number of Hypoglycemic Events	24 hours	This outcome captures the number of hypoglycemic events that occurred throughout the entire study
Percentage of Time Spent With BG > 180 mg/dl	24 hours
Number of Participants Achieving a Stable Glucose Response to Insulin Dosing	24 hours
Insulin and Glucagon Levels During the Closed-loop Admission as Compared to the Comparable 24 Hour Period During the Open Loop Admission of Diabetic Subjects	24 hours
Set Point Using CGM Data as the Input to the Controller for Future Studies	24 hours	The algorithm in the Bionic Pancreas must have a pre-specified target glucose it is trying to achieve in order to make dosing decisions. Using data from this study, investigators planned to determine what an appropriate glucose target should be for future studies.
Insulin and Glucagon Levels During Closed Loop and Open Loop Admissions of Diabetic Subjects Compared to the Comparable 24 Hour Period During the Admission of Non-diabetic Subject	24 hours