Comparison of Accuracy of Freestyle Libre Pro and Medtronic iPro2 Continuous Glucose Monitoring Systems in Pregnancy

There are limited data on head-to-head performance of Freestyle Libre Pro (FSL-Pro) and blinded Medtronic iPro2 continuous glucose monitoring system in pregnancy. In this prospective observational study, women with hyperglycemia in pregnancy (n = 42) underwent simultaneous FSL-Pro and Medtronic iPro2 sensor insertion and self-monitoring of blood glucose using Contour Plus meter (reference). The overall mean absolute relative difference (MARD) for iPro2 and FSL-Pro systems were 8.0% +/- 9.2% and 19.0% +/- 12.7%, respectively. At hypoglycemic range, both sensors performed less accurately (MARD: 18.0% and 16.8%, respectively), whereas iPro2 showed higher accuracy at euglycemic (8.2% and 19.3%, respectively) and hyperglycemic (6.8% and 18.0%, respectively) ranges. On Bland-Altman analysis, iPro2 and FSL-Pro underestimated glucose by 0.01 and 1.09 mmol/L, respectively. The ISO criteria were fulfilled for 88.5% and 44.9% of all values, respectively. To conclude, iPro2 was more accurate; however, both sensors demonstrated inaccuracy at hypoglycemic range, highlighting the need for refinements in the current generation of sensors to address this problem.