884-P: Discrepancies in Key Metrics of Glycemic Control between Retrospective Continuous Glucose Monitoring System and Flash Glucose Monitoring in Adult Patients with Type 1 Diabetes

Abstract

Limited data on head-to-head comparisons between the flash glucose monitoring (FGM) system (FreeStyle Libre®, FSL) and retrospective continuous glucose monitoring (CGM) system (IproTM2) were available. The study aimed to compare glycemic metrics derived from two devices in adult patients with type 1 diabetes (T1D). Adult T1D patients with HbA1c of 7 to 10% were recruited and randomized to adopt FSL or self-monitoring blood glucose in the 24-week trial (NCT03522870). In the FSL group, glucose was simultaneously measured by FSL and IproTM2s on patients’ different arms for 14 days at 12 and 24 weeks. Data collected on the day of insertion and detachment and those of insufficient quality (<90%) were excluded. Each FSL glucose value was aligned with the closet IproTM2 value(lag time<2min). Glycemic metrics were calculated via Glyculator 2.0 software and differences between them were assessed. From May 2018 to November 2019, a total of 31287 paired data collected from 27 adult T1D patients (male/female 7/20; age 30.2±8.9yrs; duration 8.9[6.2,13.1]yrs; HbA1c 7.6±0.8%) were included. The median number of days with available CGM data was 11.3(9.9,12.0). Agreement between the two devices’ measurements was satisfactory (R2=0.85, P<0.001). Time in range 70-180mg/dl (%, TIR) was significantly lower in FSL than that in IproTM2 (59.5[49.3,66.7] vs. 62.3[51.6,69.5] %, P=0.02). Significant difference in time spent below 70 and 54mg/dl(%) was observed with the higher ones in FSL group (<70mg/dl, 7.2[5.6,13.8] vs. 4.5[2.0,9.2] %, P=0.02; <54mg/dl, 2.6[1.3,5.3] vs. 1.4[0.4,3.0] %, P=0.04). There were no significant differences in time spent over 180 and 250mg/dl (%), and glycemic variability including CV and MAGE (all P>0.05). In the 14-days wearing of the different devices simultaneously, there was a close agreement between FSL and Ipro2 but significant differences were observed in TIR and time spent in hypoglycemia. Disclosure Y. Zhou: None. H. Deng: None. D. Yang: None. J. Yan: None. W. Xu: None. H. Liu: None. L. Gan: None. S. Luo: None. X. Zheng: None. H. Liang: None. B. Yao: None. J. Weng: None. Funding National Key Research and Development Program of China (2017YFC1309600); Natural Science Foundation of Guangdong Province (2018A030313251)