296-OR: Diminished Sensor Performance of the Abbott Freestyle Libre Intermittently-Viewed Continuous Glucose Monitoring System (ICGMS) during Hypoglycemia and Acute Exercise in People with Type 1 Diabetes

Abstract

Aim: To determine the sensor performance of the Abbott Freestyle® Libre iCGMS during glycemic challenges and acute exercise during multiple 23-hours inpatient phases. Methods: 17 people with T1D (4 women, age 34.9 ± 15.5 years, BMI 25.9 ± 3.0 kg/m2, HbA1c 7.3 ± 1.4% (56 ± 15 mmol/mol)) on multiple daily injections were included in the study, consisting of four 23-hours inpatient phases with meal-induced glycemic disturbances and 45-minutes moderate-intensity cycle ergometer exercises. iCGMS was compared to reference blood glucose by median absolute relative difference (MARD), Clarke Error Grid (CEG) and Bland-Altman (intention-to-treat). Results: The overall MARD (IQR) during the inpatient phases (excluding exercise) was 12.9% (6.1-21.5%), during hypoglycemia 31.6% (14.0-46.8%), euglycemia 14.5% (7.0-22.5%) and hyperglycemia 8.7% (4.6-14.6%). The overall Bland-Altman analysis showed a bias (95% LoA) of 19.8 mg/dL (-78.37-118 mg/dL) and CEG is illustrated in the Figure. The overall MARD during exercise was 29.8% (17.5-39.8%), during hypoglycemia 45.1% (35.2-51.1%), euglycemia 30.7% (18.7-39.2%) and hyperglycemia 16.3% (10.0-22.8%). Conclusion: iCGMS interstitial glucose readings should be used cautiously during hypoglycemia and exercise and need confirmatory blood glucose measurements. Disclosure O. Moser: Research Support; Self; Abbott, Dexcom, Inc., Novo Nordisk A/S. M.L. Eckstein: Research Support; Self; Novo Nordisk A/S. O. McCarthy: None. R. Deere: None. J. Pitt: None. D.M. Williams: None. J. Hayes: None. S.C. Bain: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Merck Sharp & Dohme Corp., Mylan, NAPP Pharmaceuticals Limited, Novo Nordisk A/S, Sanofi. R.M. Bracken: None. Funding Novo Nordisk A/S