An Outpatient Pump Shutoff Pilot Feasibility and Safety Study

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.

Inclusion criteria

• Clinical diagnosis of type 1 diabetes and using daily insulin therapy for at least one year and an insulin infusion pump for at least 6 months
• Age >=18.0 years
• HbA1c <=8.0%
• Availability of internet access for periodic upload of study data
• Experience using the Medtronic pump and CGM and investigator is confident that subject will use CGM on a near-daily basis during the study
• Nocturnal hypoglycemia meeting the following criterion based on CGM download: during the most recent 15 nights with CGM glucose data (must be within the past 42 days), one or more nights with a sensor glucose value <=70 mg/dL.

Exclusion criteria

• Diabetic ketoacidosis in the past 3 months
• Hypoglycemic seizure or loss of consciousness in the past 6 months
• History of seizure disorder (except for hypoglycemic seizure)
• Coronary artery disease or heart failure
• Cystic fibrosis
• Current use of oral/inhaled glucocorticoids, beta-blockers or other medications, which in the judgment of the investigator would be a contraindication to participation in the study.
• History of ongoing renal disease (other than microalbuminuria). Creatinine level to have been obtained within the last year if subject has diabetes of >10 years duration or is over 50 years of age. If creatinine is > 1.5 mg/dL, the subject is excluded.
• History of liver disease
• Medical or psychiatric condition that in the judgment of the investigator might interfere with the completion of the protocol such as: inpatient psychiatric treatment in the past 6 months, uncontrolled adrenal disorder, and/or abuse of alcohol
• Pregnancy: A negative urine pregnancy test will be required for all premenopausal women who are not surgically sterile. Subjects who become pregnant will be discontinued from the study.