Accuracy of Abott Freestyle Libre versus Dexcom G6 in a patient with pre-diabetes: a case report and review of literature

Abstract

Abstract Abbott FreeStyle Libre and Dexcom G6 represent widely employed continuous glucose monitoring (CGM) systems globally. However, their precision remains unexplored concerning postprandial glucose levels in individuals with pre-diabetes following the consumption of diverse dietary regimens. A 58-year-old Japanese man diagnosed with pre-diabetes (postprandial hyperglycemia) underwent simultaneous monitoring using Abbott FreeStyle Libre and Dexcom G6 following the consumption of diverse diets. In the pre-meal state, both systems exhibited comparable and reliable values (around 80–100 mg/dl). However, around 60 minutes following meals containing specific amounts of carbohydrates (approximately above 50 g), FreeStyle Libre demonstrated a more pronounced acceleration in the increase and peak glucose values compared to G6. These discrepancies were further validated through self-monitoring of blood glucose (SMBG) measurements, confirming the less accurate performance of FreeStyle Libre under these conditions. To this end, it appears that fermented products (beans, yogurt, cheese) could suppress postprandial glucose spikes. The study results suggest that, when compared to G6, FreeStyle Libre yielded elevated glucose values and exhibited reduced accuracy in measuring postprandial glucose levels following the ingestion of a specific amount of carbohydrates in a patient with pre-diabetes.