Comparison of glucose monitoring between Freestyle Libre Pro and iPro2 in patients with diabetes mellitus

AIMS/INTRODUCTION: Flash and continuous glucose monitoring systems are becoming prevalent in clinical practice. We directly compared a flash glucose monitoring system (FreeStyle Libre Pro [FSL‐Pro]) with a continuous glucose monitoring system (iPro2) in patients with diabetes mellitus. MATERIALS AND METHODS: Glucose concentrations were simultaneously measured using the FSL‐Pro, iPro2 and self‐monitoring blood glucose in 10 patients with diabetes mellitus, and agreement among them was assessed. RESULTS: Parkes error grid analysis showed that the 92.9 and 7.1% of glucose values measured using the FSL‐Pro fell into areas A and B, respectively, and that 96.3, 2.8 and 0.9% of those determined using iPro2 fell into areas A, B and C, respectively. The median absolute relative differences compared with self‐monitoring blood glucose were 8.1% (3.9–12.7%) and 5.0% (2.6–9.1%) for the FSL‐Pro and iPro2, respectively. Analysis of 5,555 paired values showed a close correlation between FSL‐Pro and iPro2 glucose values (ρ = 0.96, P < 0.01). Notably, 65.3% of all glucose values were lower for the FSL‐Pro than the iPro2. Median glucose values also decreased by 3.3% for the FSL‐Pro compared with the iPro2 (177.0 [133.0–228.0] vs 183.0 [145.0–230.0] mg/dL, P < 0.01). The difference in glucose values between the two systems was more pronounced in hypoglycemia. The median absolute relative difference between FSL‐Pro and iPro2 during hypoglycemia was much larger than that during euglycemia and hyperglycemia. CONCLUSIONS: Both the FSL‐Pro and iPro2 systems are clinically acceptable, but glucose values tended to be lower when measured using the FSL‐Pro than the iPro2. Agreement was not close between these systems during hypoglycemia.