Objective: Time in range (TIR) is a novel measure of glucose control endorsed by an international consensus group. TIR describes the percentage of TIR (3.9-10mmol/l), time above range (TAR >10mmol/l) and time below range (TBR, <3.9mmol/l) over a given time period. Given the increased use of FreeStyle Libre (FSL) in the UK we were keen to explore the glucose ranges commonly reported in routine clinical practice.

Methods: The ABCD UK FreeStyle Libre audit invited clinicians to submit routine clinical data from FSL users to a secure web-based tool. Data from 101 UK hospitals were analysed using R3.5.0. Linear regression analysis was used to compare the baseline predictors of TIR . TIR was categorised as internationally accepted (3.9-10mmol/l) or individualised (any range other than 3.0-10mmol/l).

Results: Data were available for 10,370 FSL users; age 38 (±18.7) years, 54% female, diabetes duration 16 (±49) years, and BMI of 25.2 (±16.5) kg/m2. Follow-up HbA1c and TIR data was available for 2191 patients. Of those with both follow-up HbA1c and TIR data, in only 343 (15%) cases did clinicians report on the internationally accepted TIR (3.9-10mmol/l), with a median TIR of 43% (27%-56%). Taking both international and individualised TIR together, 221 (10%) had ≥70% TIR, 822 (37%) ≥50% TIR and 1372 (62%) <50% TIR over 14 days. On multivariate regression analysis baseline age (beta=0.13 P<0.0001, number of FSL scans per day (beta= 0.22, P<0.0001) and baseline HbA1c (beta=-0.45, P<0.0001) were associated with higher TIR. The internationally accepted median TBR (<3.9mmol/l) was 6% (3-11) in this cohort.

Conclusion: This population-based study of FSL users demonstrates a limited uptake of the internationally recommended TIR of 3.9-10mmol/l. There is a need for greater awareness of the international recommendations for TIR measures; only a small proportion of people with type 1 diabetes achieve their goals; the number of scans per day predicts greater TIR.


E.G. Wilmot: Advisory Panel; Self; Abbott, Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Medtronic. Speaker’s Bureau; Self; Abbott, Eli Lilly and Company, Insulet Corporation, Novo Nordisk Inc., Sanofi. H. Deshmukh: None. J. Patmore: None. T. Sathyapalan: Research Support; Self; Amgen, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Novo Nordisk A/S. Other Relationship; Self; Ipsen Biopharmaceuticals. C. Walton: Speaker’s Bureau; Spouse/Partner; Celgene, LEO Pharma, Novartis Pharmaceuticals Corporation. R. Herring: None. R.E. Ryder: Consultant; Self; GI Dynamics Inc. Other Relationship; Self; Novo Nordisk A/S.

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