Feasibility Study of Closed Loop Control in Type 1 Diabetes Using Heart Rate Monitoring as an Exercise Marker

Not Applicable

Completed

Conditions: Type 1 Diabetes Mellitus

Interventions: Device: Heart rate informed SSM+HMM

Registration Number: NCT01582139

Lead Sponsor: University of Virginia

Brief Summary: The purpose of this study is to see if the Artificial Pancreas Platform (AP Platform = Cell Phone + Closed Loop Control) can successfully control blood sugar in people with type 1 diabetes mellitus on insulin pump therapy in a hospital setting. Investigators will also be studying to see if information about heart rate can help the AP Platform reduce hypoglycemia related to exercise.

Detailed Description: The combination of the Control to Range system and the cell phone is called the "Artificial Pancreas (AP) Platform". The purpose of this study is to see if this investigational technology can help control blood sugar in people with type 1 diabetes mellitus on insulin pump therapy can be successfully used and supervised in a hospital setting. This study is also being done to see if giving information about heart rate to the Closed-to-Range System can reduce hypoglycemia as it relates to exercise. Subjects will exercise on an exercise bike in the clinical research unit. During one exercise testing session, the Closed-to-Range System will receive information about your heart rate (Experimental Condition). During the other exercise testing session, the Control to Range System will not receive information about your heart rate (Control Condition). This part of the study is being done to see whether heart rate information helps the Closed-to-Range System reduce the occurrences of exercise-related hypoglycemia.

The Closed-to-Range system has two parts (modules) that can work together or separately.

A. The Safety Supervision Module (SSM) helps to prevent low blood sugars. It can reduce the amount of basal insulin that the pump is delivering and alert you if carbohydrates are needed to help prevent a low blood sugar. This module will be active at all times during the operation of the Closed-to-Range System.

B. The Hyperglycemia Mitigation Module (HMM) helps to prevent high blood sugars. It can instruct the insulin pump to deliver small boluses to help prevent high blood sugar. It can also help warn you of a possible pump problem if the blood sugar level is not responding to the insulin as it should.

The Closed-to-Range System works with the insulin pump and continuous glucose monitor to help keep the blood sugar in a desired range (80-180 mg/dL) during the day and help avoid hypoglycemia during the night.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 12

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Experimental Condition: (Heart-Rate Informed SSM+HMM)	Heart rate informed SSM+HMM	An experimental condition involving an exercise session where the Safety Supervision Module + Hyperglycemic Mitigation Module (SSM+HMM) is informed about heart rate

Primary Outcome Measures

Name	Time	Method
Hypoglycemic Events	26 hours (x2 admissions)	Plasma glucose based number of hypoglycemic events, defined as consecutive plasma readings below 70mg/dl to measure the capacity of the system to protect patients against the risk of hypoglycemia. Two events separated by only one Yellow Springs Instrument (YSI) value over 70 are considered to form a single event.

Secondary Outcome Measures

Name	Time	Method
Low Blood Glucose Index	26 hours (x2 admissions)	A measure of the risk of hypoglycemia. It quantifies the frequency and the extent of low BG readings. A LBGI \< 2.5 is associated with a low-risk of hypoglycemia, LBGI 2.5-5 is associated with a moderate risk of hypoglycemia, and LBGI \> 5 is associated with a high-risk of hypoglycemia.
Average Glucose Drop	26 hours (2x admissions)	Average glucose drops at specific time points after the onset of exercise; defined as the difference between plasma glucose at onset of exercise and the glucose values reached at 40 and 60 min post onset of exercise.
Time in Range	26 hours (x2 admissions)	Percent time spent within target (70-180 mg/dL) range.