Possible Relationship between the Deteriorated Accuracy of Intermittent-Scanning Continuous Glucose Monitoring Device
Masao Toyoda1, Takashi Murata, Yushi Hirota
1Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. m-toyoda@is.icc.u-tokai.ac.jp.
Objective:
We previously reported the mean average relative difference (MARD) of the sensor glucose (SG) of the first-generation FreeStyle Libre with the original algorithm, an intermittent scanning continuous glucose monitoring (isCGM) device, was 15.6% in the Effect of Intermittent-Scanning Continuous Glucose Monitoring to Glycemic Control Including Hypoglycemia and Quality of Life of Patients with Type 1 Diabetes Mellitus Study (ISCHIA Study). In the present study, we aimed to further analyze its accuracy in detail by conducting a post-hoc analysis of the study.
Methods:
The ISCHIA Study was a multicenter, randomized, cross-over trial to assess the efficacy of isCGM. The SG levels of isCGM and the measured capillary blood glucose (BG) levels of 91 participants were used for the analysis.
Results:
Bland-Altman analysis showed bias of -13.0 mg/dl when the SG levels were compared to the BG levels, however no proportional bias was observed (r = 0.085). MARD of the participants without and with contact dermatitis were 15.0 ± 6.0% and 27.4 ± 21.4% (P = 0.001), respectively.
Conclusion:
There was negative bias in the SG levels of isCGM compared to the BG levels. There is a possibility that the complication of the contact dermatitis during isCGM use may be related with deteriorated accuracy of the SG levels.
