An Outpatient Pump Shutoff Pilot Feasibility and Safety Study (PSO1)

• Mean morning blood glucose (mg/dL) [ Time Frame: 21 study nights ] [ Designated as safety issue: Yes ]
  The primary safety outcome will be evaluated by comparing the intervention and control nights and nights with vs. without actual shut-off of the pump for several measures of hyperglycemia such as mean morning blood glucose (mg/dL).
  
  
• Morning blood glucose >250 mg/dL [ Time Frame: 21 days ] [ Designated as safety issue: Yes ]
  The primary safety outcome will be evaluated by comparing the intervention and control nights and nights with vs. without actual shut-off of the pump for several measures of hyperglycemia such as morning glucose measured with home glucose meter >250 mg/dL.
  
  
• Morning blood ketones >1.0 mmol/L [ Time Frame: 21 days ] [ Designated as safety issue: Yes ]
  The primary safety outcome will be evaluated by comparing the intervention and control nights and nights with vs. without actual shut-off of the pump for several measures of hyperglycemia such as morning blood ketones >1.0 mmol/L.
  
  
• Morning urine ketones moderate or large [ Time Frame: 21 days ] [ Designated as safety issue: Yes ]
  The primary safety outcome will be evaluated by comparing the intervention and control nights and nights with vs. without actual shut-off of the pump for several measures of hyperglycemia such as morning urine ketones moderate or large.
  
  

• Mean sensor glucose overnight [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
  
• Percentage of sensor glucose values 71 to 180 mg/dL [ Time Frame: Overnight from system activation to deactivation in the morning upon awakening ] [ Designated as safety issue: No ]
  
• Percentage of sensor glucose values 71 to 180 mg/dL [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
  
• Area under the curve sensor glucose >180 mg/dL [ Time Frame: Overnight from system activation to deactivation in the morning upon awakening ] [ Designated as safety issue: No ]
  
• Area under the curve sensor glucose >180 mg/dL [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
  
• Percent of nights with CGM value >250 mg/dL [ Time Frame: 21 study nights ] [ Designated as safety issue: No ]
  
• Episodes of Diabetic Ketoacidosis [ Time Frame: 21 study nights ] [ Designated as safety issue: Yes ]
  
• Episodes of severe hypoglycemia [ Time Frame: 21 study nights ] [ Designated as safety issue: Yes ]
  

Patients who meet all eligibility criteria will use the study system overnight at home for about 5 nights to demonstrate their ability to use the system and submit study data to the Coordinating Center.

Patients who successfully demonstrate their ability to use the system as described above will be eligible for the randomized trial phase. This phase consists of use of the full system as an outpatient for approximately 21 nights:

• Each night the blood glucose level will be checked with the study blood glucose (BG) meter and used to perform a calibration of the CGM. The calibration must occur no more than 90 minutes prior to activation of the system. NOTE: Patients will be instructed to calibrate the CGM per manufacturer guidelines.
• Then the system will be activated, linking the CGM and insulin pump to the computer at the bedside.
• A randomization schedule on the laptop will be used to determine whether the 'pump shut off' application will be active that night or not.
• Patients will be blinded as to whether the pump shut off is active when a session is initiated each night.
• There will not be an alarm if the pump shuts off. The CGM alarm will be set to 60 mg/dL. When a CGM alarm occurs, the patient will be asked to measure the blood glucose with a BG meter, if he/she is aware of the alarm.
• The time period for outcome assessment each night will be from the time the system is activated until it is turned off in the morning.
• Pump shut off, when it occurs, will be for up to 2 hours. Multiple instances of pump suspension can occur if there are recurrent predictions of hypoglycemia during the night.
• Patients will be asked to check blood glucose with the study BG meter, blood ketones with the study ketone meter, and urine ketones with a ketone strip each morning prior to breakfast and enter the results on the study laptop. The patient will be instructed to contact the study physician if the blood glucose or ketone readings are out of an expected range. Patients will be contacted if these morning safety values are not reported as required or are out of range.
• Patients will be asked to record all overnight carbohydrate intake on the study laptop.
• Patients will be asked to perform periodic data uploads using the study laptop. Monitoring processes will ensure that the patient is contacted if these uploads do not occur as required, or if review of an upload reveals any extreme, prolonged episodes of low or high blood glucose readings, or elevated morning blood glucose, blood ketone, or urine ketone values.

Upon completion of the study, patients as well as study clinicians will be asked to complete a questionnaire regarding use of the study system.

There will a follow-up visit after completion of 21 successful nights of study system use. A successful night of study system use is defined as use of the system for at least four hours. Phone contacts with the patients will be made once a week.