Safety of Flash Glucose Monitoring System using Free Style Libre Pro<sup>®</sup> in Patients with Diabetes in the Clinic

Levels of blood glucose and hemoglobin A1c (HbA1c) are useful parameters to treat diabetes mellitus. However, daily fluctuations in blood glucose levels, as in postprandial hyperglycemia, nocturnal hypoglycemia, and silent hypoglycemia, are difficult to monitor. Daily glycemic variability is implicated in the onset of diabetes and progression of consequent. Flash glucose monitoring (FGM) system is the latest medical technology that can be used to keep track of daily glucose fluctuation, but FGM is not widespread because of limitations related to insurance coverage and other factors. Therefore, we investigated the safety of FGM using Free Style Libre Pro® (Abbott Japan Co., Ltd.) to spread FGM into general clinics. This study was conducted on 50 patients with diabetes or borderline diabetes who wanted to use Free Style Libre Pro® during outpatient visits. While using Free Style Libre Pro®, 2 patients had uncomfortable sensation on the skin, when they came in contact with the sensor. There were no adverse events that were objective symptoms or subjective symptoms, such as itching or pain, in all patients. The systolic and diastolic blood pressure and pulse rate remained unchanged before and after using Free Style Libre Pro® (130.48±14.84 mmHg vs 131.48±15.24 mmHg, p＝0.69; 73.48±10.36 mmHg vs 72.22±13.99 mmHg, p＝0.24; 82.34±13.60 bpm vs 82.92±11.91 bpm, p＝0.67, respectively). There was no significantly change in the levels of blood glucose and HbA1c (171.84±69.56 mg/dL vs 161.16±70.52 mg/dL, p＝0.15; 8.27±1.54％ vs 8.12±1.42％, p＝0.28, respectively).