Type 1 Diabetes
Conditions
Keywords
Type 1 diabetes, Artificial pancreas, Closed-loop system, Postprandial glucose control, Hypoglycemia, Insulin, Glucagon
Brief summary
In previous studies, investigators have studied if a pre-meal insulin bolus based on estimated carbohydrate meal size would alleviate the burden of carbohydrate counting without a significant degradation in postprandial glucose control. With this strategy, the patient would only have to evaluate the size of the meal in terms of carbohydrate (snack, regular, large or very large). It is however important to establish the safety of this simplified meal bolus approach. The safety of overestimating a meal insulin bolus in the context of closed-loop strategy needs to be assessed. For ethical reasons, only dual-hormone closed-loop will be tested. Investigators hypothesize that dual-hormone closed-loop with overestimated meal size bolus will not increase time below 4.0 mmol/L compared to dual-hormone closed-loop with an adequately estimated meal size bolus.
Interventions
Interventions will be undertaken 1 to 5 days after sensor insertion. Subjects will be admitted at the research center at 7:00. Subject's pump will be substituted with the study pump and an additional pump containing glucagon will be installed. At 7:00, closed-loop will be initiated. At 9:00, a standardized breakfast (45g CHO) will be served. Study subjects will consume the same meal on the two intervention days. During the intervention, patients will be allowed to do sedentary activities. Patients will be allowed to consume caffeine during the intervention, but will have to replicate their caffeine consumption on both interventions. The intervention day will end at 13:00.
DRUGInsulin
Participant's usual fast-acting insulin analog will be used: Lispro (Humalog), Aspart (NovoRapid) or Glulisine (Apidra).
DRUGGlucagon
Glucagon (Eli Lilly) will be used during dual-hormone closed-loop strategy.
Sponsors
Institut de Recherches Cliniques de Montreal
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Males and females ≥ 18 years old. 2. Clinical diagnosis of type 1 diabetes for at least one year. 3. The subject will have been on insulin pump therapy for at least 3 months and currently using a fast acting insulin analog (Lispro, Aspart or Glulisine). 4. Last (less than 3 months) HbA1c ≤ 10%. 5. Currently using carbohydrate counting as the meal insulin dose strategy.
Exclusion criteria
1. Clinically significant microvascular complications: nephropathy (estimated glomerular filtration rate below 40 ml/min), neuropathy (especially diagnosed gastroparesis) or severe proliferative retinopathy as judged by the investigator. 2. Recent (\< 3 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery. 3. Pregnancy. 4. Severe hypoglycemic episode within 1 month of screening. 5. Agents affecting gastric emptying (Motilium®, Prandase®, Victoza®, Byetta® and Symlin®) as well as oral anti-diabetic agents (Metformin, SGLT-2 inhibitors and DPP-4 inhibitors) if not at a stable dose for 3 months. Otherwise, these medications are acceptable and will be kept stable during the entire protocol. 6. Oral steroids unless patients present a low stable dose (e.g. 10 mg or less of prednisone per day or physiological doses, less than 35 mg/day, of hydrocortisone Cortef®). Inhale steroids at stable dose in the last month are acceptable. 7. Other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator (e.g. unstable psychiatric condition). 8. Failure to comply with team's recommendations (e.g. not willing to change pump parameters, follow algorithm's suggestions, etc).
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Percentage of time below 4.0 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
Secondary
| Measure | Time frame |
|---|---|
| Percentage of time of glucose concentrations between 4.0 and 8.0 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Percentage of time of glucose concentrations between 4.0 and 10.0 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Percentage of time of glucose concentrations below 3.1 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Area under the curve of glucose values below 4.0 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Area under the curve of glucose values below 3.1 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Mean glucose | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Total number of hypoglycemic event below 3.1 mmol/L | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Total carbohydrate intake for hypoglycemia correction | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Total insulin delivery | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Total glucagon delivery | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
| Number of patients with at least one hypoglycemic event with or without symptoms | The outcome measure will be calculated over the 4 hours following the breakfast meal. The 4-hour period is from 9:00 to 13:00. |
Countries
Canada
Outcome results
None listed