closed-loop control of glucose levels after meal intake in adults with type 1 diabetes

Conditions: Type 1 Diabetes

Summary: closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosage based on the sensor's readings. a dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormones: insulin and glucagon. the objective of this project is to assess whether a dual-hormone closed-loop strategy would alleviate the burden of carbohydrate counting from patients with type 1 diabetes (t1d) without a significant degradation in post-meal glucose control. our primary hypothesis is that meal-announcement strategy (pre-meal cho-independent bolus) is equivalent to meal-and-carbohydrate-announcement strategy (full cho-matching bolus) during closed-loop regulation of glucose levels in adults with t1d. our secondary hypothesis is that closed-loop strategy with meal-announcement strategy (pre-meal cho-independent bolus) or meal-and-carbohydrate-announcement strategy (full cho-matching bolus) is better than conventional pump treatment in regulation of glucose levels in adults with t1d.

closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosages based on the sensor's readings. a dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormone: insulin and glucagon. each patient will be admitted three times to a clinical research facility. in the meal-and-carbohydrate-announcement visit, patients will eat 3 meals accompanied with a matching insulin bolus (depending on the carbohydrate content of the meal) and glucose levels will be subsequently regulated using dual-hormone closed-loop system. in the meal-announcement visit, patients will eat the 3 same meals but will inject only a partial insulin bolus (not depending on carbohydrate content of the meal) and the remaining needed insulin will be delivered based on glucose sensor excursions as part of closed-loop operation. in the control visit, patients will use conventional pump therapy to regulate glucose levels.

Eligibility criteria:
inclusion criteria: * males and females ≥ 18 years of old. * clinical diagnosis of type 1 diabetes for at least one year. * the subject will have been on insulin pump therapy for at least 3 months. * last (less than 3 months) hba1c ≤ 12%. exclusion criteria: * 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. * recent (\< 3 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery. * ongoing pregnancy. * severe hypoglycemic episode within two weeks of screening. * medication likely to affect with the interpretation of the results because of their well known impact on gastric emptying: motilium®, prandase®, victoza®, byetta® and symlin®. * known or suspected allergy to the trial products, meal contents including nuts, peanuts, dairy products or eggs. * unusual nutritional habits (e.g. vegetarians) * other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator. * failure to comply with team's recommendations (e.g. not willing to eat snack, not willing to change pump parameters, etc). * unreliable carbohydrate counting or lack of insulin to carbohydrate ratios * problems with venous access

Keywords: type 1 diabetes hypoglycemia insulin glucagon closed-loop system artificial pancreas carbohydrate counting