101-LB: Eighteen-Month Use of Closed-Loop Control (CLC): A Randomized, Controlled Trial

While the use of CLC systems is increasing, data on durable use for >1 year are limited. We present 18-month data on a recently approved CLC system (Control-IQ, Tandem Diabetes Care) in a randomized controlled trial with follow-up extension phase. The study had 164 participants with T1D (14-71 years old) who for this analysis were divided in 3 groups: Group 1: CLC for 6 months, then continued CLC to study end; Group 2: CLC for 6 months, then PLGS (Basal-IQ) for 3 months, then CLC to study end; and Group 3: SAP for 6 months, then CLC to study end. Data were evaluated in 3-month intervals for the primary outcome of time in range (TIR, 70-180mg/dL) and secondary outcomes of hypoglycemia, hyperglycemia and HbA1c. Participants in Group 1 maintained significant improvements in TIR over 18 months with overall mean of 69.9% and sustained reductions in HbA1c. TIR improvement was seen within one month of initiation of CLC and retained its durability over 18 months of use. Group 2 had deterioration in time in range and HbA1c when placed on PLGS for 3 months and restored TIR and HbA1c once resuming CLC. Group 3 had persistent improvements in TIR and HbA1c after transitioning from SAP to CLC. There were 4 severe hypoglycemic events (all after month 9) and 4 DKA events. CLC use was generally 90% or higher with no trend toward decreased use over time. Sustained use of CLC over 18 months demonstrated rapid and consistent improvements in TIR, HbA1c, and hypoglycemia. Disclosure S.A. Brown: Research Support; Self; Dexcom, Inc., Insulet Corporation, Roche Diabetes Care, Tandem Diabetes Care, Tolerion, Inc. D. Raghinaru: None. B.A. Buckingham: Advisory Panel; Self; ConvaTec Inc., Medtronic. Research Support; Self; Beta Bionics, Inc., Dexcom, Inc., Insulet Corporation, Medtronic, Tandem Diabetes Care. Y.C. Kudva: Research Support; Self; Dexcom, Inc., Roche Diabetes Care. Other Relationship; Self; Abbott. L.M. Laffel: Advisory Panel; Self; Roche Diabetes Care. Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc., ConvaTec Inc., Dexcom, Inc., Insulet Corporation, Insulogic LLC, Janssen Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk Inc., Sanofi US. C.J. Levy: Consultant; Self; Dexcom, Inc. Employee; Spouse/Partner; Allergan plc. Research Support; Self; Abbott, Dexcom, Inc., Insulet Corporation. J.E. Pinsker: Advisory Panel; Self; Medtronic. Consultant; Self; Eli Lilly and Company, Tandem Diabetes Care. Research Support; Self; Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Medtronic, Tandem Diabetes Care. Speaker’s Bureau; Self; Tandem Diabetes Care. R. Wadwa: Advisory Panel; Self; Eli Lilly and Company, Medtronic. Research Support; Self; Dexcom, Inc., Eli Lilly and Company, MannKind Corporation, Medtronic, Novo Nordisk Inc., Tandem Diabetes Care. J. Lum: None. C. Kollman: Other Relationship; Self; Dexcom, Inc., Tandem Diabetes Care. R. Beck: None. B. Kovatchev: Advisory Panel; Self; Dexcom, Inc. Research Support; Self; Dexcom, Inc., Tandem Diabetes Care. Speaker’s Bureau; Self; Dexcom, Inc., Sanofi, Tandem Diabetes Care. Other Relationship; Self; Dexcom, Inc., Johnson & Johnson, Sanofi. Funding National Institute of Diabetes and Digestive and Kidney Diseases (UC4108483); University of Virginia Strategic Investment Fund (Project 88); Tandem Diabetes Care