Closed-Loop Insulin Therapy Improves Glycemic Control in Adolescents and Young Adults: Outcomes from the International Diabetes Closed-Loop Trial

Abstract

Objective: To assess the efficacy and safety of closed-loop control (CLC) insulin delivery system in adolescents and young adults with type 1 diabetes. Research Design and Methods: Prespecified subanalysis of outcomes in adolescents and young adults aged 14-24 years old with type 1 diabetes in a previously published 6-month multicenter randomized trial. Participants were randomly assigned 2:1 to CLC (Tandem Control-IQ) or sensor augmented pump (SAP, various pumps+Dexcom G6 CGM) and followed for 6 months. Results: Mean age of the 63 participants was 17 years, median type 1 diabetes duration was 7 years, and mean baseline HbA1c was 8.1%. All 63 completed the trial. Time in range (TIR) increased by 13% with CLC versus decreasing by 1% with SAP (adjusted treatment group difference = +13% [+3.1 h/day]; 95% confidence interval [CI] 9-16, P < 0.001), which largely reflected a reduction in time >180 mg/dL (adjusted difference -12% [-2.9 h/day], P < 0.001). Time <70 mg/dL decreased by 1.6% with CLC versus 0.3% with SAP (adjusted difference -0.7% [-10 min/day], 95% CI -1.0% to -0.2%, P = 0.002). CLC use averaged 89% of the time for 6 months. The mean adjusted difference in HbA1c after 6 months was 0.30% in CLC versus SAP (95% CI -0.67 to +0.08, P = 0.13). There was one diabetic ketoacidosis episode in the CLC group. Conclusions: CLC use for 6 months was substantial and associated with improved TIR and reduced hypoglycemia in adolescents and young adults with type 1 diabetes. Thus, CLC has the potential to improve glycemic outcomes in this challenging age group. The clinical trial was registered with ClinicalTrials.gov (NCT03563313).

Keywords: Adolescents; Closed-loop control insulin delivery; Time in range; Young adult.

Conflict of interest statement

D.R. has no disclosures to report. L.A.-O. has received consulting fees from Dexcom. J.E.P. reports receiving grant support, provided to his institution, consulting fees, and speaker fees from Tandem Diabetes Care, grant support, provided to his institution, and advisory board fees from Medtronic, grant support, provided to his institution, and consulting fees from Eli Lilly, grant support and supplies, provided to his institution, from Insulet, and supplies, provided to his institution, from Dexcom. B.A.B. has received research funding from Tandem, Insulet Corp., Medtronic, Beta Bionics, Lilly, Convatec, and Dexcom. He has served on advisory boards for Medtronic, Novo Nordisk, and Convatec. R.P.W. reports receiving grant support and supplies, provided to his institution, from Tandem Diabetes Care, Dexcom, Beta Bionics, Eli Lilly, and MannKind and has served as a consultant/speaker for Eli Lilly and Tandem Diabetes Care. L.E. serves as a consultant for Tandem Diabetes Care. Y.C.K. received product support from Dexcom and Roche Diabetes and has consulted for Novo Nordisk. C.J.L. reports receiving advisory board fees from Sanofi, and grant support, paid to her institution, from Dexcom, Tandem Diabetes Care, Insulet, Abbott Diabetes, Senseonics, and Lexicon Pharmaceuticals. G.P.F. conducts research supported by Medtronic, Dexcom, Abbott, Tandem, Insulet, Beta Bionics, and Lilly and has been a consultant/speaker for Medtronic, Dexcom, Abbott, Tandem, Insulet, Beta Bionics, and Lilly. R.W.B. reports receiving consulting fees, paid to his institution, from Insulet, Bigfoot Biomedical, vTv Therapeutics, and Eli Lilly, grant support and supplies, provided to his institution, from Tandem and Dexcom, and supplies from Ascenia and Roche. C.K. has received consulting fees, paid to his institution, from Bigfoot Biomedical and grant support and supplies, provided to his institution, from Tandem and Dexcom. J.W.L. reports receiving consulting fees, paid to his institution, from Animas Corporation, Bigfoot Biomedical, Tandem Diabetes Care, and Eli Lilly. S.A.B. reports receiving grant support and supplies, provided to her institution, from Tandem Diabetes Care, Insulet, and Tolerion, and supplies, provided to her institution, from Dexcom and Roche Diagnostics. L.M.L. has received consulting fees from Johnson & Johnson, Sanofi, NovoNordisk, Roche, Dexcom, Insulet, Boehringer Ingelheim, ConvaTec, Medtronic, Lifescan, Laxmi, and Insulogic.

Figures

FIG. 1.

TIR by time of day and by treatment group. Blue triangles represent the SAP group, N = 23 participants. Red circles represent the CLC group, N = 40 participants. Lines with symbols denote hourly median values and the shaded regions are defined by the 25th and 75th percentiles. CLC, closed-loop control; SAP, sensor augmented pump; TIR, time in range.

FIG. 2.

(A) TIR over 26 weeks. Blue represents SAP group, N = 23 participants. Red represents CLC group, N = 40 participants. Black dots denote mean values, horizontal lines in the boxes denote medians, and the bottom and top of the boxes represent the 25th and 75th percentiles. (B) TIR during first 28 days in the CLC group. Red represents CLC group, N = 40 participants. Black dots denote mean values, horizontal lines in the boxes are medians, and bottom and top of the boxes represent the 25th and 75th percentiles. The range of the data are narrower after day 8 because it was averaged at a participant level over 7 days instead of 1 day, and consequently there would tend to be less variability in the point estimate for each participant.