Two Way Crossover Closed Loop Study R-AP vs MPC
Study Details
Study Description
Brief Summary
An artificial pancreas (AP) is a control system for automatic insulin delivery. The investigators have implemented a missed meal bolus detection algorithm for use within an AP control system. The robust R-AP system used in this protocol has been designed to handle a variety of real-world scenarios that are critical to a high-risk patient population. The investigators will test how well the new algorithm handles missed or inaccurate meal announcements. This type of algorithm may significantly improve glucose control over the standard model predictive control (MPC) closed-loop algorithm without these new algorithm features for patients with type 1 diabetes.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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N/A |
Detailed Description
Participants will undergo two visits at OHSU that will evaluate missed meal bolus detection. Participants will arrive at approximately 7am for all visits, be monitored through the afternoon and discharged before dinner. During each of these intervention visits, participants will wear an Omnipod to deliver insulin and a Dexcom G6 CGM to measure glucose. The closed loop system will receive activity data through a Polar M600 watch worn by the participant. The studies will test the ability of the system to adapt to a missed meal bolus. Participants will eat self selected meals at 10 am and 2pm, both meals with a missed bolus, and these meals will be repeated across both study arms. For one missed meal bolus study, glucose will be controlled using the Robust R-AP closed-loop mode. During the other missed meal bolus study, glucose will be controlled using the MPC closed-loop mode. Participants will complete frequent glucose and ketone checks for safety.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: MPC AP system Participants will use the MPC AP system for automated insulin delivery for a 9 hour study visit. |
Device: MPC AP algorithm
The Model Predictive Control (MPC) insulin infusion algorithm contains a model within the controller that takes as an input the aerobic metabolic expenditure in addition to the CGM and meal inputs. The algorithm uses heart rate and accelerometer data collected on the patient's body to calculate metabolic expenditure. The metabolic expenditure then acts on the model for the insulin dynamics, whereby more energy expenditure and longer duration exercise can lead to a more substantial effect of insulin on the CGM.
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| Experimental: Robust R-AP system Participants will use the Robust R-AP system for automated insulin delivery for a 9 hour study visit. |
Device: Robust R-AP algorithm
The R-AP is a modified MPC algorithm. A new feature in the algorithm includes a model for missed meal insulin detection. The model includes estimations for carbohydrate consumption based glucose patterns to determine if that person has consumed a meal without announcing it to the system.
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Outcome Measures
Primary Outcome Measures
- AUC of postprandial glucose [4 hour period following the first meal, assessed up to 100 weeks]
Incremental AUC of postprandial glucose in the 4 hours following the start of first meal. AUC (mg/dL*min) will be calculated using a trapezoidal method, which sums all CGM values in the 4 hour period following the meal above the starting glucose.
- Percent of time with sensed glucose between 70-180 mg/dl [4 hour period following the first meal, assessed up to 100 weeks]
Assess the percent of time that the Dexcom G6 reported sensor glucose values between 70-180 mg/dl using Dexcom sensor across both arms.
Secondary Outcome Measures
- Percent of time with sensed glucose <70 mg/dl [9 hour inpatient stay both arms]
Assess the percent of time that the Dexcom G6 reported sensor glucose values less than 70 mg/dl using Dexcom sensor across the duration of the 9 hour inpatient stay.
- Number of carbohydrate treatments [9 hour inpatient stay both arms]
Assess the number of carbohydrate treatments (defined as 15 or 20 grams of carbohydrate) across both arms.
- Number of provider-administered insulin injections [9 hour inpatient stay both arms]
Assess the number of provider-administered insulin injections to treat hyperglycemia.
- Mean sensed glucose [9 hour inpatient stay both arms]
Assess the mean sensed glucose from the Dexcom G6 reported sensor glucose values across both arms.
- Percent of time with sensed glucose <54 mg/dl [9 hour inpatient stay both arms]
Assess the percent of time that the Dexcom G6 reported sensor glucose values less than 54 mg/dl using Dexcom sensor across both arms
- Percent of time with sensed glucose >180 mg/dl [9 hour inpatient stay both arms]
Assess the percent of time that the Dexcom G6 reported sensor glucose values greater than 180 mg/dl using Dexcom sensor across both arms.
- Percent of time with sensed glucose >250 mg/dl [9 hour inpatient stay both arms]
Assess the percent of time that the Dexcom G6 reported sensor glucose values greater than 250 mg/dl using Dexcom sensor across both arms.
- Mean amount of insulin delivered per day (in units/kg) [9 hour inpatient stay both arms]
Assess the mean amount of insulin delivered per day by the Omnipod through the AP system study in units/kg across both arms.
Eligibility Criteria
Criteria
Inclusion Criteria:
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Diagnosis of type 1 diabetes mellitus for at least 1 year.
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Male or female participants 18 to 65 years of age.
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Current use of an insulin pump for at least 3 months with stable insulin pump settings for >2 weeks.
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HbA1c ≤ 10.5% at screening.
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Total daily insulin requirement is less than 139 units/day.
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Willingness to follow all study procedures, including attending all clinic visits.
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Willingness to sign informed consent and HIPAA documents.
Exclusion Criteria:
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Female of childbearing potential who is pregnant or intending to become pregnant or breast-feeding, or is not using adequate contraceptive methods. Acceptable contraception includes birth control pill / patch / vaginal ring, Depo-Provera, Norplant, an IUD, the double barrier method (the woman uses a diaphragm and spermicide and the man uses a condom), or abstinence.
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Any cardiovascular disease, defined as a clinically significant EKG abnormality at the time of screening or any history of: stroke, heart failure, myocardial infarction, angina pectoris, or coronary arterial bypass graft or angioplasty. Diagnosis of 2nd or 3rd degree heart block or any non-physiological arrhythmia judged by the investigator to be exclusionary.
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Renal insufficiency (GFR < 60 ml/min, using the MDRD equation as reported by the OHSU laboratory).
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Liver failure, cirrhosis, or any other liver disease that compromises liver function as determined by the investigator.
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Hematocrit of less than 36% for men, less than 32% for women.
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History of severe hypoglycemia during the past 12 months prior to screening visit or hypoglycemia unawareness as judged by the investigator. Participants will complete a hypoglycemia awareness questionnaire. Participants will be excluded for four or more R responses.
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History of diabetes ketoacidosis during the prior 6 months prior to screening visit, as diagnosed on hospital admission or as judged by the investigator.
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Adrenal insufficiency.
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Any active infection.
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Known or suspected abuse of alcohol, narcotics, or illicit drugs.
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Seizure disorder.
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Active foot ulceration.
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Severe peripheral arterial disease characterized by ischemic rest pain or severe claudication.
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Major surgical operation within 30 days prior to screening.
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Use of an investigational drug within 30 days prior to screening.
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Chronic usage of any immunosuppressive medication (such as cyclosporine, azathioprine, sirolimus, or tacrolimus).
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Bleeding disorder, treatment with warfarin, or platelet count below 50,000.
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Allergy to aspart insulin.
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Current administration of oral or parenteral corticosteroids.
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Any life threatening disease, including malignant neoplasms and medical history of malignant neoplasms within the past 5 years prior to screening (except basal and squamous cell skin cancer).
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Beta blockers or non-dihydropyridine calcium channel blockers.
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Current use of any medication intended to lower glucose other than insulin (ex. use of liraglutide).
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Gastroparesis
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Any clinically significant disease or disorder which in the opinion of the Investigator may jeopardize the participant's safety or compliance with the protocol.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Oregon Health and Science University | Portland | Oregon | United States | 97239 |
Sponsors and Collaborators
- Oregon Health and Science University
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Investigators
- Principal Investigator: Peter Jacobs, PhD, Oregon Health and Science University
- Principal Investigator: Jessica Castle, MD, Oregon Health and Science University
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- 23343
- 5R01DK120367-04