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Diabetes Assistant (DiAs) Control-to-Range (CTR) Nocturnal Closed-Loop Camp Study

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ClinicalTrials.gov Identifier: NCT01973413
Recruitment Status : Completed
First Posted : October 31, 2013
Results First Posted : August 15, 2014
Last Update Posted : April 24, 2015
Sponsor:
Collaborator:
Stanford University
Information provided by (Responsible Party):
Marc Breton, University of Virginia

Study Type Interventional
Study Design Allocation: Randomized;   Intervention Model: Crossover Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Condition Diabetes Mellitus, Type 1
Interventions Device: Diabetes Assistant (DiAs)
Device: Tandem t:slim Insulin Pump
Device: Dexcom G4 Platinum sensor
Enrollment 32
Recruitment Details  
Pre-assignment Details  
Arm/Group Title Inpatient Study Camp Study
Hide Arm/Group Description The first phase of this study tested the feasibility of initializing the DiAs CTR system in a clinical research center. We tested the procedures that would occur with the camp studies, from consenting the subjects, obtaining morning glucose readings, initializing the sensor in the early afternoon, having some light activity in the evening, a bedtime snack, and initializing the closed-loop system within 30 minutes before they go to bed. We also tested how the system would perform using the same calibration and blood glucose monitoring that would be done at camp. In the inpatient study mimicked some camp activities by having the subjects have 20-30 minutes of aerobic activity in the afternoon and in the evening after dinner. The data from the inpatient studies was reviewed by the Data Safety Monitoring Board (DSMB) before we proceeded with the Phase 2 summer camp studies.

The second phase of this proposal was the "in-camp" studies. The same health care providers that conducted the inpatient studies conducted the camp studies. They monitored all campers on closed-loop control in real-time. Participants were randomized to either closed-loop (experimental) or sensor-augmented therapy (control) for the first night and then crossed over every other night to the other therapy over the course of the 5- to 6-day camp session (i.e. on DiAs CTR every other night). Since participants were not always successfully completing a closed-loop control night, the pattern could not hold throughout the entire trial. Thus, there are numerous intervention sequences.

Those assigned to DiAs closed-loop control were remotely monitored throughout the night. Those assigned to the control group were not monitored remotely overnight, but they were wearing Dexcom G4 Platinum sensors with active low and high sensor glucose alarms.

Period Title: Overall Study
Started 12 20
Completed 11 20
Not Completed 1 0
Arm/Group Title Inpatient Study Camp Study Total
Hide Arm/Group Description The first phase of this study tested the feasibility of initializing the DiAs CTR system in a clinical research center. We tested the procedures that would occur with the camp studies, from consenting the subjects, obtaining morning glucose readings, initializing the sensor in the early afternoon, having some light activity in the evening, a bedtime snack, and initializing the closed-loop system within 30 minutes before they go to bed. We also tested how the system would perform using the same calibration and blood glucose monitoring that would be done at camp. In the inpatient study mimicked some camp activities by having the subjects have 20-30 minutes of aerobic activity in the afternoon and in the evening after dinner. The data from the inpatient studies was reviewed by the Data Safety Monitoring Board (DSMB) before we proceeded with the Phase 2 summer camp studies.

The second phase of this proposal was the "in-camp" studies. The same health care providers that conducted the inpatient studies conducted the camp studies. They monitored all campers on closed-loop control in real-time. Participants were randomized to either closed-loop (experimental) or sensor-augmented therapy (control) for the first night and then crossed over every other night to the other therapy over the course of the 5- to 6-day camp session (i.e. on DiAs CTR every other night). Since participants were not always successfully completing a closed-loop control night, the pattern could not hold throughout the entire trial. Thus, there are numerous intervention sequences.

Those assigned to DiAs closed-loop control were remotely monitored throughout the night. Those assigned to the control group were not monitored remotely overnight, but they were wearing Dexcom G4 Platinum sensors with active low and high sensor glucose alarms.

Total of all reporting groups
Overall Number of Baseline Participants 12 20 32
Hide Baseline Analysis Population Description
[Not Specified]
Age, Continuous  
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 12 participants 20 participants 32 participants
15.3  (2.1) 15.3  (2.9) 15.3  (2.6)
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 12 participants 20 participants 32 participants
Female
6
  50.0%
10
  50.0%
16
  50.0%
Male
6
  50.0%
10
  50.0%
16
  50.0%
HbA1c   [1] 
Mean (Standard Deviation)
Unit of measure:  Percent of glycated hemoglobin
Number Analyzed 12 participants 20 participants 32 participants
8.7  (0.7) 8.1  (1.1) 8.4  (1.0)
[1]
Measure Description: Glycated hemoglobin, estimate of average blood glucose over past 3 months
Diabetes Duration   [1] 
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 12 participants 20 participants 32 participants
7.6  (4.6) 5.6  (3.5) 6.4  (3.9)
[1]
Measure Description: Time since diagnosis of type 1 diabetes
1.Primary Outcome
Title Percent Time Near Normoglycemia
Hide Description

Percent of time in a glucose target range of 70-150 mg/dl during camp study.

Participants were randomized to either closed-loop (experimental) or sensor-augmented pump therapy (control) for the first night and then crossed over every other night to the other therapy over the course of the 5- to 6-day camp session. Thus there were ~60 nights of data for each intervention. However, data from closed-loop nights during which there were technical problems such as infusion set failure, sensor error >20%, or pump failure resulting in a >60-min interruption to closed-loop control were removed to allow for analysis of algorithm performance. Only nights with a minimum of 5 hours of closed-loop were included, and all glucose data were included in the analysis. For comparison, only data from nights during which sensor error was, <20% with a minimum of 5 hours were included in the control group.

Time Frame 6 nights
Hide Outcome Measure Data
Hide Analysis Population Description
Data from OCL nights during which there were technical problems (infusion set failure, sensor error >20%, pump failure with >60-min interruption to closed-loop) were removed. Only nights with a minimum of 5h of OCL were included. For control, only data from nights where sensor error was <20% with a minimum of 5h were included.
Arm/Group Title Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Hide Arm/Group Description:

Subjects will use the Diabetes Assistant (DiAs) and will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. Subjects will be remotely monitored throughout the night in real time.

Diabetes Assistant (DiAs): The Control-to-Range (CTR) algorithm that will be used in DiAs will automatically adjusts insulin delivery in response to CGM values that have exceeded or are predicted to exceed the bounds of a pre-specified blood glucose range.

Subjects will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. They will not use the Diabetes Assistant (DiAs) nor have remote monitoring.
Overall Number of Participants Analyzed 20 20
Overall Number of Units Analyzed
Type of Units Analyzed: Total Nights of Data
41 39
Median (Inter-Quartile Range)
Unit of Measure: percentage of time
73
(50 to 89)
52
(24 to 83)
Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Experimental: Closed-Loop Control, Control: Sensor-Augmented Pump Therapy
Comments [Not Specified]
Type of Statistical Test Non-Inferiority or Equivalence
Comments Significance level of 0.05, 90% power, required 48 nights of OCL and 48 control nights to detect a 20% improvement.
Statistical Test of Hypothesis P-Value =0.037
Comments [Not Specified]
Method Wilcoxon (Mann-Whitney)
Comments [Not Specified]
2.Secondary Outcome
Title Overnight Glucose
Hide Description

Mean overnight glucose during camp study.

Participants were randomized to either closed-loop (experimental) or sensor-augmented pump therapy (control) for the first night and then crossed over every other night to the other therapy over the course of the 5- to 6-day camp session. Thus there were ~60 nights of data for each intervention. However, data from closed-loop nights during which there were technical problems such as infusion set failure, sensor error >20%, or pump failure resulting in a >60-min interruption to closed-loop control were removed to allow for analysis of algorithm performance. Only nights with a minimum of 5 hours of closed-loop were included, and all glucose data were included in the analysis. For comparison, only data from nights during which sensor error was, <20% with a minimum of 5 hours were included in the control group.

Time Frame 6 nights
Hide Outcome Measure Data
Hide Analysis Population Description
Data from OCL nights during which there were technical problems (infusion set failure, sensor error >20%, pump failure with >60-min interruption to closed-loop) were removed. Only nights with a minimum of 5h of OCL were included. For control, only data from nights where sensor error was <20% with a minimum of 5h were included.
Arm/Group Title Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Hide Arm/Group Description:

Subjects will use the Diabetes Assistant (DiAs) and will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. Subjects will be remotely monitored throughout the night in real time.

Diabetes Assistant (DiAs): The Control-to-Range (CTR) algorithm that will be used in DiAs will automatically adjusts insulin delivery in response to CGM values that have exceeded or are predicted to exceed the bounds of a pre-specified blood glucose range.

Subjects will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. They will not use the Diabetes Assistant (DiAs) nor have remote monitoring.
Overall Number of Participants Analyzed 20 20
Overall Number of Units Analyzed
Type of Units Analyzed: Total Nights
41 39
Mean (Standard Deviation)
Unit of Measure: mg/dL
140  (18) 147  (36)
Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Experimental: Closed-Loop Control, Control: Sensor-Augmented Pump Therapy
Comments [Not Specified]
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value =0.340
Comments [Not Specified]
Method Wilcoxon (Mann-Whitney)
Comments [Not Specified]
3.Secondary Outcome
Title Glycemic Events
Hide Description

Number of nights with >= 1 hypo- and hyperglycemic event occurring overnight during the camp study.

Participants were randomized to either closed-loop (experimental) or sensor-augmented pump therapy (control) for the first night and then crossed over every other night to the other therapy over the course of the 5- to 6-day camp session. Thus there were ~60 nights of data for each intervention. However, data from closed-loop nights during which there were technical problems such as infusion set failure, sensor error >20%, or pump failure resulting in a >60-min interruption to closed-loop control were removed to allow for analysis of algorithm performance. Only nights with a minimum of 5 hours of closed-loop were included, and all glucose data were included in the analysis. For comparison, only data from nights during which sensor error was, <20% with a minimum of 5 hours were included in the control group.

Time Frame 6 nights
Hide Outcome Measure Data
Hide Analysis Population Description
Data from OCL nights during which there were technical problems (infusion set failure, sensor error >20%, pump failure with >60-min interruption to closed-loop) were removed. Only nights with a minimum of 5h of OCL were included. For control, only data from nights where sensor error was <20% with a minimum of 5h were included.
Arm/Group Title Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Hide Arm/Group Description:

Subjects will use the Diabetes Assistant (DiAs) and will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. Subjects will be remotely monitored throughout the night in real time.

Diabetes Assistant (DiAs): The Control-to-Range (CTR)algorithm that will be used in DiAs will automatically adjusts insulin delivery in response to CGM values that have exceeded or are predicted to exceed the bounds of a pre-specified blood glucose range.

Subjects will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. They will not use the Diabetes Assistant (DiAs) nor have remote monitoring.
Overall Number of Participants Analyzed 20 20
Overall Number of Units Analyzed
Type of Units Analyzed: Total Number of Nights
41 39
Measure Type: Number
Unit of Measure: nights with >= 1 event
Hyperglycemic (>250mg/dl) 4 4
Hypoglycemic (<70mg/dl) 7 14
Time Frame [Not Specified]
Adverse Event Reporting Description [Not Specified]
 
Arm/Group Title Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Hide Arm/Group Description

Subjects will use the Diabetes Assistant (DiAs) and will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. Subjects will be remotely monitored throughout the night in real time.

Diabetes Assistant (DiAs): The Control-to-Range (CTR)algorithm that will be used in DiAs will automatically adjusts insulin delivery in response to CGM values that have exceeded or are predicted to exceed the bounds of a pre-specified blood glucose range.

Subjects will wear a Tandem t:slim insulin pump and a Dexcom G4 Platinum sensor with active low and high sensor glucose alarms. They will not use the Diabetes Assistant (DiAs) nor have remote monitoring.
All-Cause Mortality
Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Affected / at Risk (%) Affected / at Risk (%)
Total   --/--   --/-- 
Hide Serious Adverse Events
Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Affected / at Risk (%) Affected / at Risk (%)
Total   0/32 (0.00%)   0/20 (0.00%) 
Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 0%
Experimental: Closed-Loop Control Control: Sensor-Augmented Pump Therapy
Affected / at Risk (%) Affected / at Risk (%)
Total   0/32 (0.00%)   0/20 (0.00%) 
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Results Point of Contact
Layout table for Results Point of Contact information
Name/Title: Marc Breton, PhD
Organization: Univeristy of VIrginia
Phone: 434-982-6484
EMail: mb6nt@virginia.edu
Layout table for additonal information
Responsible Party: Marc Breton, University of Virginia
ClinicalTrials.gov Identifier: NCT01973413    
Other Study ID Numbers: 001-Stanford
First Submitted: October 24, 2013
First Posted: October 31, 2013
Results First Submitted: June 27, 2014
Results First Posted: August 15, 2014
Last Update Posted: April 24, 2015