Hybrid Closed-Loop (HCL) Technology Improves Glycemic Control among Historically Marginalized Youth with Type 1 Diabetes (T1D)

Background: Non-Hispanic Black (NHB) youth with T1D are more likely to have suboptimal glycemic control and less likely to use HCL systems or to be included in clinical trials. We evaluated changes in glycemic control with use of Tandem t:slim X2 insulin pump with Control-IQ technology in this historically underrepresented population in T1D research. Methods: This prospective non-randomized pilot study enrolled 15 pump naïve, publicly insured, NHB youth (Mage 14.6 ± 3.7) with T1D and A1c ≥10% in a 6 month trial of HCL use. Changes in A1c (n=13) and CGM-measured glycemia at baseline versus the final 90 days of the study for those with <70% wear time (n=12) were assessed using paired t-tests and Wilcoxon signed rank tests. Results: Thirteen participants (87%) completed the study; one was removed after 2 episodes of diabetic ketoacidosis (DKA) and the other for protocol non-adherence. A1c decreased from 11.7±1.3% to 9.6±1.6% (p=0.001). Average sensor glucose decreased from 281±53 to 225±30 mg/dL and time in range (TIR) increased by 4.5±8.5 hours/day from 18.5±15.0% to 37.1±10.3% (p=0.007). Time above range (TAR) <180 mg/dL decreased by 4.6±4.5 hours/day from 81.3±15.4% to 62.0±10.3% (p=0.007). There were no changes in time below range <70 mg/dL (p=0.72). DKA did not increase (0.67 episodes/person-year pre-enrollment vs 0.58 episodes/person-year during study intervention). Conclusions: Tandem t:slim X2 insulin pump with Control-IQ technology use in NHB youth with suboptimal T1D control was associated with improvements in average glucose, TIR, and TAR. The theoretical risk for increased risk of DKA is frequently cited as a barrier to HCL use in this population, however there was no increase in rates of DKA during the study period. These glycemic improvements without increased risk emphasize the importance of supporting equitable access to diabetes technology among all people with T1D. Disclosure B.E.Marks: Research Support; Tandem Diabetes Care, Inc., Dexcom, Inc., Medtronic. J.Grundman: Research Support; American Diabetes Association, Dexcom, Inc. S.Meighan: Speaker's Bureau; Dexcom, Inc. M.Monaghan: Employee; National Institute of Diabetes and Digestive and Kidney Diseases, Research Support; American Diabetes Association. R.Streisand: None. A.G.Perkins: Research Support; Tandem Diabetes Care, Inc., Dexcom, Inc. Funding National Institutes of Health (K23DK129827); Tandem Diabetes Care, Inc. (TDC20210226); Dexcom, Inc.