Clinical Startup of the 670G Closed Loop Insulin Delivery System

3.1 Initial Procedures After reviewing the patient's interest and eligibility, the investigators will obtain informed consent and assent as appropriate. The investigators will start the clinical process for starting an insulin infusion pump. This typically involves attending a pre-pump class (for those patients naïve to insulin pump therapy) and starting the process to obtain insurance coverage for the 670G system.

The investigators plan to track the insurance approval process, typically the number of calls and faxes required, as well as the result - approved vs not approved.

3.2 Pump Run-in (for those patients new to insulin infusion pumps) For patients who are insulin pump naïve the investigators will start on 670G insulin pump without the glucose sensor activation as per our existing clinical protocol. This may occur at a group visit.

3.3 Initial Visit

During at an initial visit, the following procedures will be performed:

• A clinically obtained HbA1c assessment, typically done via fingerstick and DCA2000 (but any equivalent NGSP-certified point-of-care or laboratory based measurement within 2 weeks prior to enrollment acceptable)
• Collection of medical history information including

• Demographics (date of birth, gender, race and ethnicity), diabetes history, medical history, concomitant medications
• Collect data for diabetes devices (eg meters, sensors, pumps)
• Brief clinical physical exam including vital signs and skin assessment
• CareLink account creation and sharing of access if this is not already done At this visit, patients will be taught how to insert and use the system glucose sensor.

3.3.1 Initial Week on the 670G System During the following week, the system (with both pump and sensor active) will be active with the PLGS on.

3.4 System Start Visit After the initial PLGS week, patients will be taught, perhaps as a group, the closed loop system and the system activated. (Note: multiple days of system data are required using the pump and sensor prior to the 670G system being capable of delivering additional insulin for hyperglycemia. Therefore, this stage of the start-up is a function of the system requirements.)

3.5 Weekly CareLink Download and Calls For each of the next four weeks, the patient/family will upload data into the CareLink system and the data will be reviewed by a member of the clinical team. Adjustments to system settings will be suggested to the family as clinically appropriate.

3.6 Routine 3, 6, 9 and 12 Month Clinical visits At a routine clinical visits the investigators will obtain an interval medical history, physical examination, collect and review of diabetes management data from all diabetes devices with an eye towards improving glycemic control. The investigators will collect adverse event information regarding severe hypoglycemia and diabetic ketoacidosis. Patients will be advised of suggested changes in pump settings

Inclusion criteria

• Clinical diagnosis of type 1 diabetes The diagnosis of type 1 diabetes is based on the investigator's judgment; C peptide level and antibody determinations are not required.
• Clinically planning to and be able to start the Medtronic 670G closed loop system
• Age greater than 7.00 years at the initiation of the 670G system
• Total daily insulin use of great than 8.0 units per day over a 1 week period
• Willing and able (access to internet from home) to download information into the Medtronic CareLink software

Exclusion criteria

• 1) Current or planned pregnancy (for the next 12 months)