The International Diabetes Closed Loop (iDCL) Trial: Protocol 4

This results shown is mean percent time in range 70-180 mg/dL.

Superiority for time in range 70-180 mg/dL and non-inferiority for time <54 mg/dL measured with CGM will be considered primary endpoints, analyzed using a hierarchical gatekeeping testing procedure

CGM-measured mean glucose (mg/dL)

CGM time > 180 mg/dL

CGM time > 250 mg/dL

CGM time < 70 mg/dL

CGM time < 54 mg/dL (Superiority)

CGM measured glucose variability measured with the coefficient of variation (CV)

CGM-measured % in range 70-140 mg/dL

CGM measured glucose variability measured with the standard deviation (SD)

CGM time < 60 mg/dL

Low blood glucose index (LBGI) by CGM with higher index indicating higher risk of hypoglycemia. LBGI ≤ 1.1 is associated with minimal risk of hypoglycemia, 1.1 < LBGI ≤ 2.5 is associated with a low risk of hypoglycemia, 2.5 < LBGI ≤ 5.0 is associated with a moderate risk of hypoglycemia, and LBGI > 5.0 is associated with high risk of hypoglycemia.

CGM time > 300 mg/dL

High Blood Glucose Index (HBGI) is a measure of Hyperglycemic Risk based on frequency and severity of hyperglycemic events. HBGI < 4.5 is associated with lower risk of hyperglycemia, 4.5 < HBGI < 9 is associated with a moderate risk of hyperglycemia and HBGI > 9 is associated with high risk of hyperglycemia

Hemiglobin A1c measured after completing each study arm

Number of participants HbA1c <7.0% after completing each study arm

Number of participants HbA1c <7.5% after completing each study arm

Diabetes Distress Scale for adults has 28 items rated on a 6 point Likert scale that ranges from 1 (not a problem) to 6 (a very serious problem). The total score is the mean of the sum of responses and ranges from 1 to 6 where a higher score indicates greater degrees of diabetes distress.

The GMSS for Type 1 Diabetes contains four subscales as well as a total scale. For this measure, total scale is reported. To calculate the total scale (higher scores indicate greater satisfaction): Mean of all items 1-15 (reverse code items: 2-7, 9, 11-13, and 15) which are all scored on a 5 point scale (1-5) (Minimum Total Scale Score is 1, Maximum Total Scale Score is 5)

Hypoglycemia Confidence Scale has 20 items which are rated on a 4-point Likert Scale ranging from 1 (not confident at all) to 4 (very confident) with higher scores indicating higher confidence in dealing with hypoglycemia. A single score is computed by calculating the mean of the sum of all items and ranges from 1 to 4.

The INSPIRE questionnaire assesses user expectations and experiences with Insulin Delivery Systems: Perceptions, Ideas, Reflections, Expectations (INSPIRE). Survey total scores are computed by calculating the mean of the sum of all item ratings then multiplying the mean by 25 to scale the score to a range from 0 to 100. Higher scores indicate a more positive perception of insulin delivery systems. Items are rated on a 5 point Likert scale ranging from 0 (strongly disagree) to 4 (strongly agree). The Adult survey has 22 items, the Teens/Adolescents survey has 17 items and the Parent survey has 21 items.

System Usability Scores (SUS)-composite score from 0 to 100 with higher scores indicate better perceived usability

Total Daily Insulin (units)

Basal: bolus insulin ratio

Calculate all CGM metrics listed above (including the primary outcome) for: All 24 hours of the day, Daytime only (06:00AM to 00:00AM), Nighttime only (00:00AM to 06:00AM).

Severe hypoglycemia (per protocol)

Diabetic ketoacidosis (per protocol)

Ketone events defined as day with ketone level >1.0 mmol/L

CGM-measured hypoglycemic events (>15 minutes with glucose concentration <54 mg/dL) in each arm.

CGM-measured hyperglycemic events (>15 minutes with glucose concentration >300 mg/dL) in each arm.

BG-measured Hypoglycemic Events (One BG Record <54 mg/dL

Worsening of HbA1c from baseline to 26 weeks by >0.5%

Other serious adverse events (SAE) and serious adverse device events (SADE)

Adverse device effects (ADE)

Unanticipated adverse device effects (UADE)

For this outcome, mean +/- SD or summary statistics appropriate to the distribution will be tabulated by treatment group

For this outcome, severe hypoglycemia event rate per 100 person-years will be calculated as a rate.

For this outcome, number of participants with diabetic ketoacidosis (DKA) will be tabulated.

For this outcome, the diabetic ketoacidosis event rate per 100 person-years will be calculated as a rate.

For this outcome, the adverse event rate per 100 person-years calculated as a rate.