Feasibility of Closed-loop Automated Insulin Delivery System by Primary Care & Endocrinology, in Person & Via Telehealth

Inclusion Criteria

• Age 18-85 years, BMI ≥ 18.5, have had clinical type 1 diabetes for at least one year, and have taken insulin for at least 1 year
• Prescription diabetes medication regimen stable for > 1 month, including any adjunctive anti-diabetic medications (except for medications that will not affect the safety of the study and are not expected to affect any outcome of the study, in the judgment of the site principal investigator)
• This does not include changes to any insulin doses, including basal rates/long-acting insulin doses, carbohydrate to insulin ratios and correction factors
• Willing to wear one Dexcom CGM transmitter and sensor (sensor must be changed every 10 days), and one infusion set that must be replaced at least every 3 days.
• Endocrinology practice criterion is that diabetes is managed using sensor-augmented insulin pump therapy or artificial pancreas therapy for ≥ 3 months)
• Primary care practice criteria are that diabetes is managed by multiple daily insulin injections (insulin-pump naïve).
• TH group criterion is that participant must have hardware and internet access capable of 2-way video and audio communication

Exclusion Criteria

• Unable to provide informed consent (e.g. impaired cognition or judgment)
• Unable to safely comply with study procedures and reporting requirements (e.g. impairment of vision or dexterity that prevents safe operation of the bionic pancreas, impaired memory)
• Unable to speak and read English, as iLet BP support materials and device menus are currently available in English only.
• Plan to change usual diabetes regimen in the next 3 months including before and during participation in the study
• This would include changing from MDI to pump or from pump to MDI, and starting a CGM if not previously used
• This would not include changes to any insulin doses, including basal rates/long acting insulin doses, carbohydrate to insulin ratios and correction factors
• Current use of non-FDA approved closed-loop or hybrid closed-loop insulin delivery system (e.g. "Loop" or "Open APS")
• Unwilling to switch to lispro or aspart for the duration of the study's iLet arm (e.g. from Fiasp or Lyumjev)
• Known hemoglobinopathy (sickle cell trait is not an exclusion)
• Current participation in another diabetes-related clinical trial, has a medical condition, or use of a medication that, in the judgment of the investigator, could compromise the results of this study or the safety of the participant
• History of diabetes due to cystic fibrosis, pancreatitis, or other pancreatic disease, including pancreatic tumor or insulinoma, or history of complete pancreatectomy
• Have a history of intermittently required glucocorticoid treatment (e.g., but not limited to, for the treatment of asthma, inflammatory bowel disease).
• A1c >11.0% (most recent value up to 1 year prior acceptable; if none available or >1 year prior, participant will be instructed to obtain A1c through their usual care provider and to make copy of result available to study team)
• History of diabetic ketoacidosis (DKA) within the past month
• Electrically powered implants (e.g. cochlear implants, neurostimulators) that might be susceptible to RF interference
• Established history of allergy or severe reaction to adhesive or tape that must be used in the study
• Currently treated with GLP-1 analogue, thiazolidinedione (TZD), sulfonylurea, pramlintide, or SGLT-2 inhibitor medication (use more than 3 months prior to enrollment is acceptable)

a. If using metformin, participants: i. Must be on a stable dose for 1 month prior to enrollment ii. Metformin can be continued while the iLet is used

• Pregnant (positive urine HCG), breast feeding, plan to become pregnant in the next 6 months, or premenopausal participants who are sexually active without use of contraception
• Renal failure on dialysis or chronic renal disease with a GFR or eGFR 2 years prior, participant will be instructed to obtai