Effect of Arterialization on Venous Blood Glucose Concentrations and Implications for Observed Continuous Glucose Monitoring Accuracy.

Background Heating of the arm and/or hand ("arterialization") is sometimes used in continuous glucose monitoring (CGM) performance studies with the reported aim of reducing differences between venous and capillary glucose concentrations. In this study, the effect of heating on venous glucose concentrations and CGM accuracy was investigated. Methods A heating pad set to 50 °C (122 °F) was used with 20 participants to heat either the dominant or non-dominant arm and hand. Venous and capillary samples were obtained every 15 minutes on both arms throughout each of three 6-hour glucose challenges. CGM sensors were worn on each upper arm for each of the three visits. Results Heating of the arm led to a median increase in venous glucose concentrations of +1.4%. No similar effect on capillary concentrations was observed. As a result, the median capillary to venous difference decreased from +5.9% in the non-heated arm, to +4.2% in the heated arm. CGM accuracy observed in this study was affected by the selection of heated venous, non-heated venous, or capillary glucose concentrations as comparator data. The heating effect was more pronounced with rapidly decreasing glucose concentrations. Temperatures on the skin did not exceed 40 °C (104 °F). No adverse events or protocol deviations were associated with the use of the heating pad. Conclusions Heating of the arm led to a small increase in venous glucose concentrations, but venous concentrations did not reach the level of capillary glucose concentrations. CGM accuracy observed in this study varied depending on the selected comparator data.