Evaluation of Fiasp® (Fast Acting Insulin Aspart) in 670G Hybrid Closed-Loop Therapy

This will be a randomized cross-over blinded study and to see how the 670G pump responds to the introduction of Fiasp® insulin. Subjects enrolled in the study will have a 2 week period of optimization with weekly assessments of their Carelink download before entering the blinded phase of the study. They will use their usual home insulin during the optimization phase. They will then be started on their first blinded insulin (aspart or Fiasp®) which they will use for 2 weeks, before they cross-over to the other insulin.

Inclusion criteria

• Clinical diagnosis of type 1 diabetes and using 670G pump for at least 1 month, and willing to have the 670G pump downloaded into a Carelink Clinical research database.
• The diagnosis of type 1 diabetes is based on the investigator's judgment; C-peptide level and antibody determinations are not needed.
• Age ≥18 years
• Using Novolog or Fiasp® insulin at time of enrollment
• Willing to use Fiasp® insulin
• Total daily insulin dose is at least 0.3 units/kg/day
• Usual carbohydrate intake is at least 60 grams a day, and willing to have at least 25 grams of carbohydrates for breakfast
• For females, not currently known to be pregnant
• An understanding of and willingness to follow the protocol and sign the informed consent
• Willing to have photographs taken of their infusion sites
• Willing to download their 670G pump every 1-2 weeks to a research Carelink account
• Willingness to answer a brief online questionnaire every 2 weeks
• Must be able to understand spoken or written English
• For subjects participating in Part 2 of this study they will need to be using Fiasp® as part of their usual care
• Hemoglobin A1c between 6 and 10% at the time of enrollment

Exclusion criteria

• Pregnant or lactating females
• No hypoglycemic seizure or loss of consciousness in the past 6 months
• Severe episode of DKA in the 6 months prior to study enrollment that was unrelated to an infusion set failure
• No known cardiovascular events in the last 6 months
• No active proliferative diabetic retinopathy
• Known tape allergies
• Current treatment for a seizure disorder
• Cystic fibrosis
• Active infection
• A known medical condition that in the judgment of the investigator might interfere with the completion of the protocol
• Inpatient psychiatric treatment in the past 6 months
• Presence of a known adrenal disorder
• If on antihypertensive, thyroid, anti-depressant or lipid lowering medication, with lack of stability on the medication for the past 2 months prior to enrollment in the study
• Abuse of alcohol
• Dialysis or renal failure
• Known eGFR <60%

Note: Adequately treated thyroid disease and celiac disease do not exclude subjects from enrollment.