1037-P: Glucose Control following Missed and Late Meal Boluses with a Medtronic Enhanced-Hybrid Closed-Loop (E-HCL) System

Background: A missed or late meal insulin bolus can impact glycemia in type 1 diabetes (T1D). Aim: To study glucose control after missed and late meal boluses in T1D adults using a prototype enhanced hybrid closed-loop (E-HCL) system (Medtronic) providing automated basal insulin and correction boluses. Methods: Twelve T1D adults (median HbA1c 6.8% [IQR 6.2-7.2] | 51mmol/mol [44-55] participated. After 1-week run-in at home in Open Loop, E-HCL was activated during 1-week supervised hotel phase followed by 3 weeks free-living at-home. Participants consumed a standardized 40g carbohydrate dinner in the supervised phase. Four hours of post-prandial glucose data following a standard bolus pre-meal in E-HCL at home were compared in a pairwise manner to 1) Pre-meal bolus in Open Loop Run-In; 2) 20minute Late bolus in E-HCL supervised; 3) Missed bolus in E-HCL supervised using Wilcoxon Signed-Rank Test. Results: Late bolus was associated with mild hypoglycemia and higher glucose variability; missed bolus was associated with hyperglycemia (Table). Overall time in CL was 99.98%. E-HCL at home vs. Open Loop (run-in) had greater time-in-70-180mg/dL range (85.3 vs. 75.0%, p=0.003). There was no severe hypoglycemia or ketoacidosis. Conclusions: While glucose excursions were modest, the administration and timing of meal boluses influenced post-meal glycemia in well-controlled T1D adults using E-HCL. Disclosure M.H. Lee: Research Support; Self; Medtronic. Speaker9s Bureau; Self; AstraZeneca. S. Vogrin: None. B. Paldus: Other Relationship; Self; Australian Diabetes Society, JDRF, Medtronic. H. Jones: None. V.R. Obeyesekere: None. C.M. Sims: Stock/Shareholder; Self; Medtronic. S.A. Wyatt: Other Relationship; Self; Animas Corporation, Medtronic. G.M. Ward: None. S.A. McAuley: Research Support; Self; JDRF, Medtronic. Speaker9s Bureau; Self; Australian Diabetes Society, Eli Lilly and Company. R. MacIsaac: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Novo Nordisk Inc. Speaker9s Bureau; Self; AstraZeneca, Novo Nordisk Inc. Other Relationship; Self; AstraZeneca, Novo Nordisk Inc. B. Krishnamurthy: None. V. Sundararajan: None. A. Jenkins: Advisory Panel; Self; Abbott, Australian Diabetes Society, Medtronic. Research Support; Self; Abbott, GlySens Incorporated, Medtronic, Mylan. Speaker9s Bureau; Self; Eli Lilly and Company, Novo Nordisk Inc. D.N. O9Neal: None.