1960-P: Estimated Treatment Effect of Time in Range 70–180 mg/dl (TIR) Greatly Differs by CGM System

Introduction and Objective: Assess the influence of the CGM system on the estimated treatment effect of % time in range 70-180 mg/dL (TIR). Methods: 23 participants wore a Dexcom G7 (DG7), FreeStyle Libre 3 (FL3), and Medtronic Simplera (MSP) simultaneously for 14 days. An artificial intervention group was created by reducing or increasing each glucose value by 10%. The TIR was calculated for each individual in the control arm (original data) and intervention arm, and the estimated treatment effect was the difference in means derived from the same CGM system. A paired t-test compared the estimated treatment effect from two different CGM systems. Results: The estimated treatment effect of TIR greatly differed by CGM system (Table). When the intervention reduced glucose by 10%, the estimated treatment effect of TIR was 3.2% using DG7, 3.8% using FL3, and 0.3% using MSP (P=0.30 comparing DG7 vs. FL3; P<0.001 comparing DG7 vs. MSP; P<0.001 comparing FL3 vs. MSP). When the intervention increased glucose by 10%, the estimated treatment effect of TIR was -5.6%, -6.0%, and -3.8%, respectively (P=0.47, P=0.006, and P=0.007, respectively). Similar results were found for % time >180 mg/dL. Conclusion: The estimated treatment effect of TIR using MSP can significantly differ from the estimated treatment effect using DG7 or FL3. Further randomized controlled trials that evaluate a treatment using two different CGM systems are needed to confirm results Disclosure P. Calhoun: None. G. Freckmann: None. M. Eichenlaub: None. D. Waldenmaier: None. C. Kollman: None. R.W. Beck: Research Support; Current; MannKind Corporation, Abbott Diabetes, Dexcom, Inc., Tandem Diabetes Care, Inc., Sequel Med Tech, DreaMed Diabetes, Ltd. Consultant; Ended; Novo Nordisk, Eli Lilly and Company. Consultant; Current; Zucara Therapeutics.