Optimising insulin doses for adolescents and adults with Type 1 diabetes using closed loop pumps.

INTERVENTION: This study involves the provision of 2 different test meals in the form of pancakes of different ingredients, a high carbohydrate (HC) meal or high fat, high protein (HFHP) meal on 8 occasions over 2 consecutive weeks. Test meals will be observed under different insulin dosing conditions. The HC test meal will be observed under 4 conditions; 1) standard bolus given in manual mode 15 minutes prior to meal delivery, 2) standard bolus (100% insulin to carbohydrate ratio) given in manual mode 25 minutes prior to meal delivery, 3) standard bolus given in auto mode 15 minutes prior to meal delivery and 4) standard bolus given in auto mode 25 minutes prior to meal delivery. The HFHP test meal will also be observed under 4 conditions; 5) dual wave bolus (70:30, 3 h) in manual mode given 15 minutes prior to meal delivery, 6) dual wave bolus using 130% ICR (70:30, 3h) in manual mode, 7) standard bolus given in auto mode 10 minutes prior to meal delivery and 8) split bolus given in auto mode with bolus 1, equivalent to 100% of the individual ICR given 15 minutes prior to meal delivery and bolus 2, equivalent to 30% of the individual ICR given 60 minutes post‐ meal delivery. Participants will be randomly allocated to receive both meal cohorts over the two weeks. Standard bolus refers to 100% of the participants insulin to carbohydrate ratio for that meal.. High Carbohydrate Meal= 90g carbohydrate, less than 10g protein. less than 10g of fat High Fat High Protein Meal= 30g carbohydrate, 50g of protein, 40g of fat All meals will be provided and made to exact measurements. The pump records insulin dosages that we can review to ensure patient compliance. Participants will have a face to face session at the Hunter Medical Research Institute where they will be provided CONDITION: Metabolic and Endocrine ‐ Diabetes Type 1 diabetes; ; Type 1 diabetes PRIMARY OUTCOME: Mean postprandial glucose excursion at 240 minutes from baseline for each condition after test meal consumption. This will be measured using a continuous glucose monitor.[Difference in mean glucose excursions at 240 mins post‐ meal. This will be measure in 30 minute intervals from baseline (0/meal consumption) until 240 minutes] SECONDARY OUTCOME: Percent time in glucose target range (3.9‐10 mmol/L)[Measured using continuous glucose monitor (cgm) from baseline (meal consumption) to 240mins] INCLUSION CRITERIA: Diagnosed with type 1 diabetes >1 year Using insulin pump therapy >6 months Glycated haemoglobin less than or equal to 10.0%