The Set-Point Study: Evaluating Effects of Changing Glucose Target on Bionic Pancreas Performance
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Type 1 Diabetes
- Sponsor
- Massachusetts General Hospital
- Enrollment
- 24
- Locations
- 1
- Primary Endpoint
- Mean Continuous Glucose Monitor (CGM) Glucose Values
- Status
- Completed
- Last Updated
- 7 years ago
Overview
Brief Summary
The current study is designed to determine the effect on mean glucose, hypoglycemia, glucagon usage, and insulin usage of adjusting upward the glucose target of the bi-hormonal bionic pancreas, and determine whether there is a target at which adequate glycemic control is achieved by an insulin-only bionic pancreas with minimal hypoglycemia.
Detailed Description
We have two specific aims: Aim 1 is to conduct an outpatient study testing multiple configurations of the bionic pancreas in 24 adult subjects with type 1 diabetes in a random cross-over study versus usual care with an insulin pump. These bionic pancreas configurations include the insulin only BP at 145 mg/dl set point, 130 mg/dl set point, 120 mg/dl set point and 110 mg/dl set point and the bihormonal BP at 130 mg/dl set point, 115 mg/dl set point and 110 mg/dl set point. These arms are all compared to usual care. Aim 2 is to evaluate the incremental utility of glucagon in the context of automated insulin delivery by the bionic pancreas in preventing hypoglycemia during exercise in the fasted state. The 130 mg/dl set points and 110 mg/dl set points also participate in this fasted exercise visit. These two set points are double blinded, so neither the subjects nor the study staff are aware which arm is bihormonal and which arm is insulin only.
Investigators
Steven J. Russell, MD, PhD
Assistant Professor of Medicine
Massachusetts General Hospital
Eligibility Criteria
Inclusion Criteria
- •Type 1 Diabetes Subjects: Age ≥ 18 years and have had clinical type 1 diabetes for at least one year, and managed using an insulin pump for ≥ 6 months Type 2 Diabetes subjects: Age ≥ 18 years and have type 2 diabetes managed with rapid acting insulin in an insulin pump, or multiple daily injections including both long acting and short acting insulin
- •Prescription medication regimen stable for \> 1 month (except for medications that will not affect the safety of the study and are not expected to affect any outcome of the study, in the judgment of the principal investigator)
- •Live within a 60 minute drive-time radius of the central monitoring location
- •Willing to remain within a 120 minute drive-time radius of the central monitoring location throughout the study
- •Have someone over 18 years of age who lives with them, has access to where they sleep, is willing to be in the house when the subject is sleeping, and is willing to receive calls from the study staff and check the welfare of the study subject if telemetry shows a technical problem or severe biochemical hypoglycemia without subject response and the subject does not answer their telephone (up to two individuals can share this role, but they must be willing to carefully coordinate with each other and the subject so that one of them is clearly designated as having this responsibility at any given time)
- •Willing to wear two infusion sets and one CGM sensor and change sets frequently (at least one new glucagon infusion set daily during bi-hormonal arms, and insulin infusion set every other day throughout the study)
- •Have a mobile phone they are willing to keep with them and answer calls from study staff
Exclusion Criteria
- •Unable to provide informed consent (e.g. impaired cognition or judgment)
- •Unable to safely comply with study procedures and reporting requirements (e.g. impairment of vision or dexterity that prevents safe operation of the bionic pancreas, impaired memory, unable to speak and read English)
- •Current participation in another diabetes-related clinical trial that, in the judgment of the principal investigator, will compromise the results of this study or the safety of the subject
- •Pregnancy (positive urine HCG), breast feeding, plan to become pregnant in the immediate future, or sexually active without use of contraception
- •Need to go outside of the designated geographic boundaries during the study
- •Current alcohol abuse (intake averaging \> 3 drinks daily in last 30 days), use of marijuana within 1 month of enrollment, or other substance abuse (use within the last 6 months of controlled substances other than marijuana without a prescription)
- •Unwilling or unable to refrain from drinking more than 2 drinks in an hour or more than 4 drinks in a day or use of marijuana during the trial
- •Unwilling or unable or to avoid use of drugs that may dull the sensorium, reduce sensitivity to symptoms of hypoglycemia, or hinder decision making during the period of participation in the study (use of beta blockers will be allowed as long as the dose is stable and the subject does not meet the criteria for hypoglycemia unawareness while taking that stable dose, but use of benzodiazepines or narcotics, even if by prescription, may be excluded according to the judgment of the principal investigator)
- •History of liver disease that is expected to interfere with the anti-hypoglycemia action of glucagon (e.g. liver failure or cirrhosis). Other liver disease (i.e. active hepatitis, steatosis, active biliary disease, any tumor of the liver, hemochromatosis, glycogen storage disease) may exclude the subject if it causes significant compromise to liver function or may do so in an unpredictable fashion.
- •Renal failure on dialysis
Outcomes
Primary Outcomes
Mean Continuous Glucose Monitor (CGM) Glucose Values
Time Frame: Days 2 and 3
Glucose values were collected from the Dexcom G4 CGM device every 5 minutes and an average (calculated mean with associated standard deviation) CGM glucose level (mg/dl) was calculated from days 2 and 3 of the study arm.
Percentage of Time With CGM < 60 mg/dl
Time Frame: Days 2 and 3
For this calculation we analyzed data from every 5 minutes of CGM data for days 2 and 3 of each study arm. We looked specifically at the percentage time of those roughly 48 hours that had any glucose values less than 60 mg/dl. The final value presented is the percent of time per 2 days of the study arm spent in a specific hypoglycemia range of less than 60 mg/dl with an associated standard deviation.
Number of Subjects Discordant for Reaching a BG < 60 mg/dl for > 2 Consecutive Plasma Glucose Measurements During Inpatient Exercise Visit
Time Frame: Day 4 in-clinic Exercise Visit (110 and 130 mg/dl arms only)
During both 110 mg/dl and 130 mg/dl arms, subjects will report for a fasted in-clinic exercise visit, with plasma blood glucose measurements obtained at least every 10 minutes
Secondary Outcomes
- Area Between the Glucose Curve and 60 mg/dl Calculated From BG Measurements(Day 4 in-clinic Exercise Visit (110 and 130 mg/dl arms only))
- Total Glucagon Dosing by the Bihormonal Bionic Pancreas From the Start of Exercise Until the End of the Visit(Day 4 in-clinic Exercise Visit (110 and 130 mg/dl arms only))
- Mean CGM Glucose(Days 1 through 3)
- Time From Start of Exercise to First BG Measurement < 60 mg/dl(Day 4 in-clinic Exercise Visit (type 1 diabetes only, 110 and 130 mg/dl arms only))
- Area Between the Glucose Curve and 60 mg/dl Calculated From CGM Measurements(Day 4 in-clinic Exercise Visit (type 1 diabetes only, 110 and 130 mg/dl arms only))
- Grams of Carbohydrates Given to the Subject to Treat Hypoglycemia(Day 4 in-clinic Exercise Visit (110 and 130 mg/dl arms only))
- Nausea Severity(Days 1-3)
- Percentage of Time Spent in: < 50 mg/dl, < 70 mg/dl, 70-120 mg/dl, 70-180 mg/dl, > 180 mg/dl, >250 mg/dl(Days 2-3)
- Percentage of Subjects With Mean CGM < 154 mg/dl(Days 2-3)
- Time From Start of Exercise to First CGM Measurement < 60 mg/dl(Day 4 in-clinic Exercise Visit (110 and 130 mg/dl arms only))