Oregon Health and Science University
Portland, Oregon, 97239, United States
NCT Number: NCT04771403
An artificial pancreas (AP) is a control system for automatic insulin delivery. Our group has implemented a fading memory proportional derivative controller (FMPD) for use within an AP control system which has been evaluated in clinical studies. However, the long action of insulin (90 minutes for peak action) makes it challenging to control insulin with a classical proportional derivative system. The study described within this protocol is designed to test the effectiveness of a new model-predictive control (MPC) AP that modulates insulin delivery based on estimated activity level. The potential benefit of this type of AP is that it handles exercise not as a discrete event, but it automatically adjusts insulin delivery based on estimated activity level calculated at every 5 minute cycle. This type of algorithm may significantly improve glucose control over our FMPD AP, which is designed only to detect exercise when activity level goes above a threshold for a specific duration of 45 minutes.
Looking for future studies?
Notify Me21 year–50 year
All sexes
Interventional
Not applicable
Portland, Oregon, 97239, United States
Participants will undergo two approximately 76 hour studies. During each of these intervention visits, participants will wear an Omnipod to deliver insulin and a Dexcom G6 CGM to measure glucose. The CGM system will provide sensed glucose data every 5 minutes. Sensed glucose data will be wirelessly transmitted via Bluetooth Low Energy (BTLE) from the Dexcom G6 transmitter to the Samsung master controller every five minutes. The smart phone will wirelessly communicate via BTLE to an Omnipod through an Omnipod PDM. During one of the studies, glucose will be controlled using the MPC AP. During another study, glucose will be controlled using the FMPD AP. The AP system will receive activity data through a Polar M600 watch worn by the participant.
Participants will arrive at the clinic at approximately 7am for the inpatient visits. Participants will eat breakfast, lunch and dinner in the clinic. Participants will perform activities of daily living and exercise using an aerobic exercise video. Participants will discharge at 7pm to go home for the remainder of the study visit and perform one exercise video session at home. Participants will return to OHSU on Day 4 for removal of all devices. The exception to this is for the first 8 participants using the MPC AP. These participants will stay at the research clinic during the day and go home to sleep each night (7pm-7am).
Healthy volunteers accepted: No
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Exclusion criteria
The Fading Memory Proportional Derivative (FMPD) insulin infusion algorithm determines insulin delivery rates based on proportional error, defined as the difference between the current CGM level and the target CGM level, and the derivative error, defined as the rate of change of the CGM. The FMPD algorithm utilizes derivative and proportional glucose errors to determine delivery rates of insulin.
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.
The Dexcom G6 CGM measures interstitial glucose through a sensor transmitter. This glucose value is reported to the MPC algorithm during this intervention.
Time frame: 12 hour inpatient stay (either Day 3 or Day 1 MPC vs. Day 1 FMPD)
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 12 hour inpatient stay (either Day 3 or Day 1 MPC vs. Day 1 FMPD).
Time frame: During each 76 hour intervention study (2 total)
Assess the percent of time that the Dexcom G6 reported sensor glucose values between 70-180 mg/dl using Dexcom sensor across both arms.
Time frame: 12 hour inpatient stay (either Day 3 or Day 1 MPC vs. Day 1 FMPD)
Assess the percent of time that the Dexcom G6 reported sensor glucose values between 70-180 mg/dl using Dexcom sensor across the duration of the 12 hour inpatient stay (either Day 3 or Day 1 MPC vs. Day 1 FMPD).
Time frame: start of the in-clinic exercise session until the start of the next meal, approximately 1 hour
Assess the percent of time that the Dexcom G6 reported sensor glucose values between 70-180 mg/dl using Dexcom sensor across both arms from the start of the in-clinic exercise session until the start of the next meal.
Time frame: start of the in-clinic exercise session until the start of the next meal, approximately 1 hour
Assess the percent of time that the Dexcom G6 reported sensor glucose values less than 70 mg/dl using Dexcom sensor across both arms from the start of the in-clinic exercise session until the start of the next meal.
Time frame: During each 76 hour intervention study (2 total)
Assess the mean number of carbohydrate treatments (defined as 15 or 20 grams of carbohydrate) across both arms.
Time frame: During each 76 hour intervention study (2 total)
Assess the mean sensed glucose from the Dexcom G6 reported sensor glucose values across both arms. The Dexcom G6 CGM updates every 5 minutes with a new CGM value for 10 days. The Dexcom G6 reads values between 40-400 mg/dL with an urgent low alert at 55 mg/dl, a low and high alert when CGM goes above or below the alert thresholds set by the user. Physiologically relevant thresholds for the Dexcom G6 CGM sensor glucose values are less than 55 mg/dl, less than 70 mg/dl, above 180 mg/dl and above 250 mg/dl. The Dexcom G6 target range is 70-180 mg/dl.
Time frame: During each 76 hour intervention study (2 total)
Assess the coefficient of variation of glucose from the Dexcom G6 reported sensor glucose values across both arms. The Dexcom G6 CGM updates every 5 minutes with a new CGM value for 10 days. The Dexcom G6 reads values between 40-400 mg/dL with an urgent low alert at 55 mg/dl, a low and high alert when CGM goes above or below the alert thresholds set by the user. Physiologically relevant thresholds for the Dexcom G6 CGM sensor glucose values are less than 55 mg/dl, less than 70 mg/dl, above 180 mg/dl and above 250 mg/dl. The Dexcom G6 target range is 70-180 mg/dl.The target coefficient of variation is 33% or lower.
Time frame: During each 76 hour intervention study (2 total)
Assess the percent of time that the Dexcom G6 reported sensor glucose values less than 54 mg/dl using Dexcom sensor across both arms
Time frame: During each 76 hour intervention study (2 total)
Assess the percent of time that the Dexcom G6 reported sensor glucose values greater than 180 mg/dl using Dexcom sensor across both arms
Time frame: During each 76 hour intervention study (2 total)
Assess the mean amount of insulin delivered per day by the Omnipod through the AP system study in units/kg across both arms.
Oregon Health and Science University
Other
A Randomized, Two-way, Cross-over Study to Assess the Efficacy of an MPC Exercise-enabled Closed-loop System vs FMPD Exercise-enabled Closed-loop System
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View the official ClinicalTrials.gov record (opens in a new tab)This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.
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